RARE DISEASE
Behavioral variant of frontotemporal dementia
Behavioral variant of frontotemporal dementia
Behavioral variant of frontotemporal dementia
Synonyms: bv-FTD
Synonyms: bv-FTD
Synonyms: bv-FTD
Drug discovery
3
drugs
With orphan designations
Overview
Behavioral variant frontotemporal dementia (bvFTD) is a neurodegenerative disorder marked by progressive personality changes, social disinhibition, apathy, loss of empathy, and executive dysfunction due to frontal/temporal lobe atrophy [1][4][6]. Pathology involves tau, TDP-43, or FUS protein aggregates [1][20]. Diagnosis relies on behavioral criteria, neuroimaging, and exclusion of biomarkers for Alzheimer’s disease [1][4]. Symptoms typically emerge between 45-65 years but can occur earlier or later [2][4][7].
Burden
Therapies
Pharmacologic: SSRIs (e.g., citalopram) for disinhibition/compulsions; cautious use of antipsychotics (e.g., quetiapine) for severe agitation [3][8][13].
Non-pharmacologic: Structured routines, caregiver education, occupational/speech therapy, and palliative care planning [3][9][14].
Avoid cholinesterase inhibitors/memantine (ineffective or harmful) [13][20].
Categories: rare genetic diseases, rare neurological diseases
Research Papers
259 drug discovery papers about Behavioral variant of frontotemporal dementia, with 5 first-in-class and 1 next-in-class emerging drug candidate forecasted to outperform the average preclinical success rate. Recent publications:
259 drug discovery papers about Behavioral variant of frontotemporal dementia, with 5 first-in-class and 1 next-in-class emerging drug candidate forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
proteins
2026-04-02 | Peripheral immune profiling in frontotemporal dementia.
Frontotemporal dementia (FTD) encompasses a heterogenous and clinically diverse group of disorders, including the behavioural variant frontotemporal dementia, the non-fluent and the semantic variants of primary progressive aphasia. While these subtypes present with distinct clinical features, emerging evidence implicates neuroinflammation as a shared pathogenic mechanism. Nevertheless, little is known regarding the status of the peripheral immune system in the pathogenesis of FTD. Blood samples were obtained from 27 individuals with a clinical diagnosis of FTD (7 behavioural variants FTD, 10 non-fluent and 10 semantic variants of primary progressive aphasia) and 25 age-matched healthy controls. The immunophenotypes of peripheral immune cell populations were assessed with multicolour flow cytometry. Regulatory T cells were isolated and co-cultured with responder T cells and proliferation was determined by 3H-thymidine incorporation. The immune-related transcriptomic profile of isolated monocytes was analysed using the NanoString Human Inflammation Panel. Plasma levels of inflammatory cytokines and chemokines were quantified using the Olink® Target 48 Cytokine panel. Our analysis demonstrated that the suppressive function of regulatory T cells on responder T cells proliferation was significantly compromised in FTD individuals compared to healthy controls (P < 0.05). Transcriptomic profiling of FTD monocytes revealed a potential dysregulation of 153 immune-related genes. Enrichment analysis showed that these genes were mainly involved in chemokine-mediated signalling pathway, monocyte and lymphocyte chemotaxis, response to interferon-gamma and positive regulation of ERK1 and ERK2 cascades. Proteomic analysis of plasma inflammatory mediators showed a significant increase in the pro-inflammatory cytokine TNFa (P < 0.05) and the chemokines CXCL10, CCL3, CCL19, CSF1 (P < 0.05) and CXCL12 (P < 0.01) in FTD individuals compared to healthy controls. These findings provide the first evidence that the immunomodulatory function of regulatory T cells is compromised in individuals with FTD. In addition, there is a dysregulation of inflammation-related gene expression in peripheral monocytes and an increase of plasma inflammatory chemokines and cytokines in FTD individuals. Further investigation is warranted to assess the therapeutic potential of restoring dysfunctional regulatory T cells and modulating the inflammatory profile in the clinical setting of FTD.
2026-02-18 | Breaking β-sheets in FUS prion-like domain preserves phase separation and function but prevents aggregation and toxicity
Abstract The RNA-binding protein Fused in Sarcoma (FUS) undergoes phase separation associated with RNA processing. However, the prion-like low complexity (LC) domain of FUS forms solid-like aggregates in neurodegenerative diseases. Whether the formation of β-sheet structure associated with pathology is also physiologically/functionally relevant is debated. Similarly, if mislocalization alone or concomitant aggregation is responsible for FUS gain-of-function toxicity remains to be probed. Here, we introduce β-sheet breaking proline residues into FUS LC with the goal of preventing cross-β-driven aggregation without disrupting essential functions and phase separation. β-sheet-deficient FUS variants maintain native-like global motions, disorder, and phase separation, but no longer show a liquid-to-solid transition (LST). Biochemical partitioning, cellular localization, and auto- and cross-regulatory functions of FUS all remain essentially unchanged. Conversely, FUS-induced neurodegeneration in several Drosophila models is drastically reduced. These findings suggest a strategy for mitigating disease-related toxicity through backbone structure modulation to prevent prion-like domain protein aggregation. GRAPHICAL ABSTRACT SUMMARY The RNA-binding protein Fused in Sarcoma (FUS) undergoes phase separation as part of its physiological function but can aberrantly aggregate into solid-like assemblies in amyotrophic lateral sclerosis and frontotemporal dementia. To dissect the role of β-sheets in both function and pathological transition, we engineered β-sheet-preventing FUS variants via targeted proline residue insertions in the prion-like disordered region. These variants retained native structure, motions, and phase behavior yet showed dramatically reduced aggregation, both as an isolated prion-like domain and in full-length FUS. Crucially, these variants maintained a panel of FUS cellular functions that depend on FUS condensation but prevented FUS toxicity in fly models of neurodegeneration. Our findings implicate β-sheets as key drivers of FUS condensate maturation and neuronal toxicity, highlighting β-sheet modulation as a therapeutic strategy against FUS-related neurodegeneration. HIGHLIGHTS Targeted proline additions disrupt β-sheet formation in FUS without altering native conformations, dynamics, or phase separation behavior β-sheet-deficient FUS variants prevent aggregation and liquid-to-solid transitions while retaining key biological functions In vivo models reveal attenuated toxicity of β-sheet-deficient FUS in Drosophila β-sheets are identified as central drivers of condensate maturation and neuronal death, offering a therapeutic entry point for modulating prion-like domain pathology
2025-11-22 | Multiplex neurodegeneration proteotoxicity platform reveals DNAJB6 promotes non-toxic FUS condensate gelation and inhibits neurotoxicity.
Neurodegenerative disorders (NDDs) are a family of diseases that remain poorly treated despite their growing global health burden. To gain insight into the mechanisms and modulators of neurodegeneration, we developed a yeast-based multiplex genetic screening platform. Using this platform, 32 NDD-associated proteins are probed against a library of 132 molecular chaperones from both yeast and humans, and an unbiased set of ~900 human proteins. We identify both broadly active and specific modifiers of our various cellular models. To illustrate the translatability of this platform, we extensively characterize a potent hit from our screens, the human chaperone DNAJB6. We show that DNAJB6 modifies the toxicity and solubility of multiple amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD)-linked RNA-binding proteins (RBPs). Biophysical examination of DNAJB6 demonstrated that it co-phase separates with, and alters the behavior of FUS containing condensates by locking them into a loose gel-like state which prevents their fibrilization. Domain mapping and a deep mutational scan of DNAJB6 revealed key residues required for its activity and identified variants with enhanced activity. Finally, we show that overexpression of DNAJB6 prevents motor neuron loss and the associated microglia activation in a mouse model of FUS-ALS.
2023-12-01 | ABCA7 Mutations Can Present as Behavioral Variant Frontotemporal Dementia Without Amyloid Pathology
Abstract Background ABCA7 was identified as an Alzheimer’s disease (AD) risk gene in 2011 through GWAS studies and subsequently its role in pathogenesis was confirmed via in‐vivo studies demonstrating loss of ABCA7 was sufficient to the trigger amyloid cascade. The most common presentation of ABCA7 loss of function mutations is an amnestic syndrome, however it less commonly can present with behavioral or motor symptoms. While the described clinical presentation can vary, almost all cases have been associated with AD pathology. Here we present three cases of bvFTD clinical syndromes in ABCA7 mutations carriers without evidence of AD pathology. Method Patients underwent a comprehensive clinical assessment including neurological history, examination, neuropsychological testing, MR brain imaging, and lumbar puncture. AD biomarkers were assessed through CSF testing. Genetic testing was obtained through CLIA certified whole genome sequencing. Result We identified three individuals with mutations in ABCA7 . Two of these individuals harbor the p.I1878M mutation and one with the p.W1214* mutation on genetic testing. They presented with behavioral variant frontotemporal dementia with no evidence of amyloid pathology on CSF biomarker testing. Conclusion We present three cases of symptomatic ABCA7 mutation carriers without evidence of underlying AD pathology. The exact function of ABCA7 is unknown, however its purported involvement in lipid transport and immune responses are common pathways in neurodegenerative disease and raises the possibility of converging disease cascades.
2023-10-23 | Anterior cingulate sulcation is associated with onset and survival in frontotemporal dementia.
Frontotemporal dementia is the second most common form of early onset dementia (<65 years). Despite this, there are few known disease-modifying factors. The anterior cingulate is a focal point of pathology in behavioural variant frontotemporal dementia. Sulcation of the anterior cingulate is denoted by the presence of a paracingulate sulcus, a tertiary sulcus developing, where present during the third gestational trimester and remaining stable throughout life. This study aims to examine the impact of right paracingulate sulcal presence on the expression and prognosis of behavioural variant frontotemporal dementia. This retrospective analysis drew its population from two clinical samples recruited from memory clinics at university hospitals in the USA and The Netherlands. Individuals with sporadic behavioural variant frontotemporal dementia were enrolled between 2000 and 2022 and followed up for an average of 7.71 years. T1-MRI data were evaluated for hemispheric paracingulate sulcal presence in accordance with an established protocol by two blinded raters. Outcome measures included age at onset, survival, cortical thickness and Frontotemporal Lobar Degeneration-modified Clinical Dementia Rating determined clinical disease progression. The study population consisted of 186 individuals with sporadic behavioural variant frontotemporal dementia (113 males and 73 females), mean age 63.28 years (SD 8.32). The mean age at onset was 2.44 years later in individuals possessing a right paracingulate sulcus [60.2 years (8.54)] versus individuals who did not [57.76 (8.05)], 95% confidence interval > 0.41, P = 0.02. Education was not associated with age at onset (β = -0.05, P = 0.75). The presence of a right paracingulate sulcus was associated with an 83% increased risk of death per year after age at onset (hazard ratio 1.83, confidence interval [1.09-3.07], P < 0.02), whilst the mean age at death was similar for individuals with a present and absent right paracingulate sulcus (P = 0.7). Right paracingulate sulcal presence was not associated with baseline cortical thickness. Right paracingulate sulcal presence is associated with disease expression and survival in sporadic behavioural variant frontotemporal dementia. Findings provide evidence of neurodevelopmental brain reserve in behavioural variant frontotemporal dementia that may be important in the design of trials for future therapeutic approaches.
gene therapies
2026-04-29 | Humanized mice carrying a pathogenic GRN deletion as a pre-clinical platform for targeted gene therapies in frontotemporal dementia.
Frontotemporal dementia (FTD) is an early onset dementia characterized by neuropathology and changes to patient behaviour. Haploinsufficiency of the gene progranulin (GRN) is a major cause of FTD, for which there are no effective therapies. Corrective gene therapies that restore GRN expression are of clinical interest, but current in vivo systems have limitations. We developed a novel strain of mice expressing a human GRN transgene bearing a four base pair deletion in exon 5 (GRNc.388_391delCAGT) that causes FTD. Characterization of mice expressing the mutant transgene (GRNmEx5) indicates that GRNmEx5 is expressed at low levels and retains partial function. The GRNmEx5 protein partially rescues progranulin nullizygous-associated neuropathology and transcriptomic dysfunction. Following characterization, we sought to determine if mice expressing GRNmEx5 in the absence of mouse progranulin (Grn-/-; GRNmEx5 mice) could enable pre-clinical gene therapy development. Using CRISPR/Cas9 with lipid nanoparticle delivery, we achieved 8.5% correction of GRNc.388_391delCAGT in target cells in Grn-/-; GRNmEx5 mice, demonstrating both effective in vivo homology-directed repair and the utility of Grn-/-; GRNmEx5 mice for developing novel progranulin-associated FTD therapies. The Grn-/-; GRNmEx5 model provides insight into progranulin biology, increases our understanding of a pathogenic variant that causes FTD, and facilitates the development of GRN gene therapies.
2024-11-01 | Genetics of Frontotemporal Dementia: an updated overview
Frontotemporal dementia (FTD) involves a category of disorders characterized by behavioral, linguistic, and mobility abnormalities resulting from neurodegeneration in the frontal and temporal lobes. FTD represents the second most common etiology of early-onset dementia, and is distinguished by a wide range of clinical features. Indeed, three clinical variants are well known: the behavioral variant (bvFTD), which is the most prevalent and predominantly associated with personality and behavioral changes, the semantic variant primary progressive aphasia (svPPA), which is associated with gradual loss of speech integrity and word meaning, and the non-fluent variant primary progressive aphasia (nfvPPA), in which patients have difficulties getting words out, with slurred speech and an abnormal voice. About 15% of FTD patients also have another neurodegenerative motor neuron disease, amyotrophic lateral sclerosis (ALS), and this co-occurrence is called FTD-ALS. About half of FTD cases are familial. The most common observed mode of inheritance for familial FTD is autosomal dominant. So far, at least ten causal genes have been implicated in the etiology of FTD. Three of these genes: the microtubule-associated protein tau (MAPT), progranulin (GRN) and chromosome 9 open reading frame 72 (C9ORF72), are the most common and are responsible for more than half of familial FTD. The remaining genes are rarely reported, and the pathological mechanisms of many of them are unclear. The causes of the remainder of the familial FTD proportion, as well as the sporadic FTD, are to be determined. We conclude that despite all the breakthroughs in discovering the etiology of FTD, the majority of work is still to be done. The discovered causal FTD genes give insights toward a better understanding of the clinical and genetic heterogeneity of FTD, and help in its early and correct diagnosis. Despite the current management of FTD relies mainly on supportive treatment several promising clinical trials showed promising results in the correction of the harmful effects caused by the mutant genes.
2024-06-05 | Peripheral expression of brain-penetrant progranulin rescues pathologies in mouse models of frontotemporal lobar degeneration.
Progranulin (PGRN) haploinsufficiency is a major risk factor for frontotemporal lobar degeneration with TAR DNA-binding protein 43 (TDP-43) pathology (FTLD-GRN). Multiple therapeutic strategies are in clinical development to restore PGRN in the CNS, including gene therapy. However, a limitation of current gene therapy approaches aimed to alleviate FTLD-associated pathologies may be their inefficient brain exposure and biodistribution. We therefore developed an adeno-associated virus (AAV) targeting the liver (L) to achieve sustained peripheral expression of a transferrin receptor (TfR) binding, brain-penetrant (b) PGRN variant [AAV(L):bPGRN] in two mouse models of FTLD-GRN, namely, Grn knockout and GrnxTmem106b double knockout mice. This therapeutic strategy avoids potential safety and biodistribution issues of CNS-administered AAVs and maintains sustained concentrations of PGRN in the brain after a single dose. AAV(L):bPGRN treatment reduced several FTLD-GRN-associated pathologies including severe motor function deficits, aberrant TDP-43 phosphorylation, dysfunctional protein degradation, lipid metabolism, gliosis, and neurodegeneration in the brain. The potential translatability of our findings was tested in an in vitro model using cocultured human induced pluripotent stem cell (hiPSC)-derived microglia lacking PGRN and TMEM106B and wild-type hiPSC-derived neurons. As in mice, aberrant TDP-43, lysosomal dysfunction, and neuronal loss were ameliorated after treatment with exogenous TfR-binding protein transport vehicle fused to PGRN (PTV:PGRN). Together, our studies suggest that peripherally administered brain-penetrant PGRN replacement strategies ameliorate FTLD-GRN relevant phenotypes including TDP-43 pathology, neurodegeneration, and behavioral deficits. Our data provide preclinical proof of concept for the use of this AAV platform for treatment of FTLD-GRN and potentially other CNS disorders.
2024-01-16 | Characterization of Progranulin Gene Mutations in Portuguese Patients with Frontotemporal Dementia.
In Portugal, heterozygous loss-of-function mutations in the progranulin (GRN) gene account for approximately half of the genetic mediated forms of frontotemporal dementia (FTD). GRN mutations reported thus far cause FTD through a haploinsufficiency disease mechanism. Herein, we aim to unveil the GRN mutation spectrum, investigated in 257 FTD patients and 19 family members from the central/north region of Portugal using sequencing methods. Seven different pathogenic variants were identified in 46 subjects including 40 patients (16%) and 6 relatives (32%). bvFTD was the most common clinical presentation among the GRN mutation patients, who showed a global pattern of moderate-to-severe frontotemporoparietal deficits in the neuropsychological evaluation. Interestingly, two mutations were novel (p.Thr238Profs*18, p.Leu354Profs*16), and five were previously described, although three of them only in the Portuguese population, suggesting a population-specific GRN mutational spectrum. The subjects harboring a GRN mutation showed a significant reduction in serum PGRN levels, supporting the pathogenic nature of these variants. This work broadens the mutation spectrum of GRN and the identification of the underlying GRN mutations provided an accurate genetic counselling and allowed the enrolment of subjects with GRN mutations (both asymptomatic and symptomatic) in ongoing clinical trials, which is essential to test new drugs for the disease.
2021-11-10 | Neuropathological and behavioral characterization of aged Grn R493X progranulin-deficient frontotemporal dementia knockin mice.
Frontotemporal lobar degeneration (FTLD) causes a spectrum of clinical presentations of frontotemporal dementia (FTD), including progressive changes in behavior, personality, executive function, and language. Up to 20% of familial FTLD cases are caused by progranulin (GRN) haploinsufficiency (FTD-GRN), with one of the most common causal variant being a nonsense mutation at arginine 493 (R493X). Recently, a genetic knockin FTD-GRN mouse model was generated bearing this GrnR493X mutation, at the analogous arginine in murine Grn. Aged, homozygous GrnR493X mice (GrnR493X/R493X) have been shown to phenotypically replicate several neuropathological hallmarks previously demonstrated in Grn null mice. We conducted a comprehensive neuropathological and behavioral assessment of 18 month old GrnR493X/R493X mice, observing a striking lysosomal dysfunction and thalamic neurodegeneration not previously described in this model, as well as a male-specific increase in generalized anxiety. These findings provide additional phenotypic markers of pathogenesis in aged GrnR493X/R493X mice that will contribute to better defining mechanisms underlying FTD-GRN, and offer relevant outcome measures for preclinical efficacy testing of novel therapeutics that target nonsense mutations leading to this devastating disease.
small molecules
2026-08-22 | Language impairments in behavioural variant frontotemporal dementia: a comparative study with semantic dementia.
Recent evidence suggests that individuals with behavioural variant frontotemporal dementia (bvFTD) may experience language changes in a similar, but less severe manner, than what is observed in semantic dementia (SD). Few studies, however, have specifically compared these patient groups or considered the cognitive underpinnings. To explore this in more depth, this study aimed to profile patterns of language performance within both "probable" and "possible" categories of bvFTD and to compare them to SD, while also considering the relationships between language and executive function measures. Participants included 106 probable bvFTD, 43 possible bvFTD, 42 SD, and 112 healthy controls from the FRONTIER clinic. Data analysed included the Addenbrooke's Cognitive Examination (ACE-III), single word processing (SYDBAT) and executive function measures (word generativity, mental flexibility, response inhibition and working memory). Naming and semantic association impairments frequently occurred in probable bvFTD (51% and 49% respectively). Approximately one quarter of possible bvFTD patients also showed language impairments. The SD pattern of pronounced naming impairment as compared to other single word tasks, was not found in the bvFTD groups. Semantic measures from the ACE-III predicted language performance in bvFTD groups; response initiation and suppression also emerged as a significant predictor. Naming and semantic association deficits commonly arise in probable bvFTD, but may also be observed in some patients with possible bvFTD. The pattern of impairments in bvFTD were not wholly consistent with those seen in SD. Both semantic and executive function measures may be associated with language performance deficits observed in bvFTD.
2026-07-29 | Single-cell transcriptomic atlas of frontoinsular cortex reveals molecular correlates of selective neuronal vulnerability in FTD.
Frontotemporal dementia (FTD) is characterized by selective neuronal vulnerability, yet the features that predispose specific neuron types to degeneration remain unclear. We performed single-nucleus RNA sequencing of frontoinsular cortex, a region affected early in behavioral variant FTD, across individuals with C9orf72-associated and sporadic FTD-MND spectrum disease. By enriching for large projection neurons, we resolved molecular subtypes of layer 5 extratelencephalic neurons, including von Economo neurons, and identified selective depletion of specific layer 2/3 and layer 5 neuron subtypes, convergent across genotypes. Despite selective neuronal loss, disease-associated transcriptional changes were convergent across excitatory neuron populations, suggesting that they reflect upstream pathophysiology or shared responses to local neurodegeneration. By relating neighborhood-level depletion in disease to gene expression in controls, we found that baseline cellular respiration and ATP synthesis predict neuronal vulnerability in disease. These findings define molecular correlates of selective neuronal vulnerability in FTD and provide a framework linking cell type and state to neurodegeneration.
2026-07-16 | Survival estimates and their predictors in genetic frontotemporal dementia: an international, retrospective, cohort study.
What drives the heterogeneity of survival estimates in genetic frontotemporal dementia is unknown. We sought to understand the natural history and predictors of disease trajectory, which are crucial not only for effective care but also for the design of therapeutic clinical trials and efficacy evaluation. In this international, cohort study, we used the Kaplan-Meier method to retrospectively assess survival estimates in patients enrolled in the GENFI cohort, which included 32 research sites located in Belgium, Canada, Finland, France, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, and the UK, and comprised participants carrying a causal C9orf72 expansion or a causal mutation in GRN or MAPT genes. Survival was calculated as the time from symptom onset to time of death or censoring date; median survival estimate for all patients was the primary endpoint. Cox proportional hazards models were used to identify predictors of survival, which were subsequently externally validated in an independent cohort. We further designed a structural equation model to assess the relationships between predictors, applying a least absolute shrinkage and selection operator method. Of 278 participants of the GENFI cohort included in this study, 160 (58%) were men and 118 (42%) were women. 162 died during follow-up (58%) and 116 were still alive (42%) on June 1, 2024, the chosen censoring date. 138 participants carried a C9orf72 expansion, 94 carried a GRN mutation, and 46 a MAPT mutation. 179 participants were diagnosed with behavioural variant frontotemporal dementia, 46 with primary progressive aphasia, and 31 with frontotemporal dementia-amyotrophic lateral sclerosis. 22 participants had other diagnoses. The median survival estimate for all patients with genetic frontotemporal dementia was 6·94 years (95% CI 6·59-7·80) from symptom onset. The median survival estimate for patients with GRN mutations was 6·63 years (6·08-7·98), for patients with a C9orf72 expansion was 7·04 years (6·45-8·77), and for patients with MAPT mutations was 8·56 years (7·06-13·50). Older age at onset, shorter disease duration from onset to enrolment in the GENFI study, clinical presentation (ie, frontotemporal dementia-amyotrophic lateral sclerosis), domain of first symptom (ie, motor or language onset), and geographical area of residency (ie, central and southern Europe) were associated with poorer prognosis. Genetic group did not directly affect survival estimates; rather its effect was mediated by age at onset and clinical phenotype. We computed a genetic frontotemporal dementia survival risk index, which can be used at an individual patient level. Our results highlight that motor impairment in addition to cognitive and behavioural symptoms should be considered when estimating prognosis in genetic frontotemporal dementia. Individual risk scores might be of help for patient stratification in future therapeutic trials, although refinement and prospective validation are now needed. Italian Ministry of Health (Ricerca Corrente), Fondation Philippe Chatrier, and Fondation Vaincre Alzheimer.
2026-06-29 | Associations of local white matter geometry with network efficiency, macrostructural abnormalities, and clinical severity in behavioural variant frontotemporal dementia.
Behavioural variant frontotemporal dementia (bvFTD), marked by profound changes in behaviour and personality, is the most common subtype of frontotemporal dementia, driven by neurodegeneration in frontotemporal regions. This neurodegeneration pattern is partially shaped by white matter abnormalities arising from the spread of protein aggregates along axonal pathways. While prior studies mainly focused on diffusion tensor imaging metrics such as fractional anisotropy and mean diffusivity, the alteration in local white matter geometry remains largely unexplored. Using a novel Director Field Analysis (DFA) method, 51 patients with bvFTD and 51 healthy controls were studied to examine alterations in the local geometry of white matter fibres in bvFTD, and their associations with macrostructural morphology, global network parameters, and clinical manifestations. Unlike the unidirectional decrease in fractional anisotropy and increase in mean diffusivity, we identified significant bidirectional alterations in white matter local geometry, characterized by increased geometric distortion in the forceps minor and dorsal cingulum and decreased distortion in widespread frontotemporal association tracts, including the inferior fronto-occipital fasciculus, superior longitudinal fasciculus, uncinate fasciculus, frontal aslant tract, and arcuate fasciculus. Patients with bvFTD also showed reduced cerebral white and grey matter volumes (both P < 0.0026), enlarged lateral ventricles and choroid plexus (both P < 0.0001), decreased global network efficiency (P = 0.0010), and increased local efficiency (P = 0.0014). Importantly, decreased white matter geometric distortion across affected tracts was strongly associated with greater clinical severity, as reflected by higher Clinical Dementia Rating scores (r = -0.68, P < 0.0001). Mediation analyses further demonstrated that white matter geometric distortion significantly mediated the effects of macrostructural atrophy and reduced global network efficiency on clinical severity. Furthermore, neuroimaging-transcriptional association analysis on the group differences in nodal efficiency of the white matter networks identified several biological processes/pathways critical for the formation and propagation of TAR-DNA-binding protein 43/microtubule-associated protein tau pathologies along axonal pathways, as well as processes related to cellular homeostasis and oligodendrocyte-related pathways that may exacerbate these proteinopathies. Our findings advance understanding of the neural bases of the functional impairments in bvFTD and suggest potential mechanistic pathways for developing novel treatment strategies.
2026-06-09 | Obsessive-compulsive Symptomatology and Caudate Tau Burden in Autopsy-confirmed FTLD-tau (P9-13.003)
To examine the relationship between obsessive-compulsive symptoms and caudate tau pathology in behavioral variant frontotemporal dementia (bvFTD) and primary progressive aphasia (PPA) due to frontotemporal lobar degeneration with tau pathology (FTLD-tau).
antibodies
2023-08-03 | Microglial activation in the frontal cortex predicts cognitive decline in frontotemporal dementia.
Frontotemporal dementia is clinically and neuropathologically heterogeneous, but neuroinflammation, atrophy and cognitive impairment occur in all of its principal syndromes. Across the clinical spectrum of frontotemporal dementia, we assess the predictive value of in vivo neuroimaging measures of microglial activation and grey-matter volume on the rate of future cognitive decline. We hypothesized that inflammation is detrimental to cognitive performance, in addition to the effect of atrophy. Thirty patients with a clinical diagnosis of frontotemporal dementia underwent a baseline multimodal imaging assessment, including [11C]PK11195 PET to index microglial activation and structural MRI to quantify grey-matter volume. Ten people had behavioural variant frontotemporal dementia, 10 had the semantic variant of primary progressive aphasia and 10 had the non-fluent agrammatic variant of primary progressive aphasia. Cognition was assessed at baseline and longitudinally with the revised Addenbrooke's Cognitive Examination, at an average of 7-month intervals (for an average of ∼2 years, up to ∼5 years). Regional [11C]PK11195 binding potential and grey-matter volume were determined, and these were averaged within four hypothesis-driven regions of interest: bilateral frontal and temporal lobes. Linear mixed-effect models were applied to the longitudinal cognitive test scores, with [11C]PK11195 binding potentials and grey-matter volumes as predictors of cognitive performance, with age, education and baseline cognitive performance as covariates. Faster cognitive decline was associated with reduced baseline grey-matter volume and increased microglial activation in frontal regions, bilaterally. In frontal regions, microglial activation and grey-matter volume were negatively correlated, but provided independent information, with inflammation the stronger predictor of the rate of cognitive decline. When clinical diagnosis was included as a factor in the models, a significant predictive effect was found for [11C]PK11195 BPND in the left frontal lobe (-0.70, P = 0.01), but not for grey-matter volumes (P > 0.05), suggesting that inflammation severity in this region relates to cognitive decline regardless of clinical variant. The main results were validated by two-step prediction frequentist and Bayesian estimation of correlations, showing significant associations between the estimated rate of cognitive change (slope) and baseline microglial activation in the frontal lobe. These findings support preclinical models in which neuroinflammation (by microglial activation) accelerates the neurodegenerative disease trajectory. We highlight the potential for immunomodulatory treatment strategies in frontotemporal dementia, in which measures of microglial activation may also improve stratification for clinical trials.
2023-03-10 | Peripheral inflammation in behavioural variant frontotemporal dementia: associations with central degeneration and clinical measures.
Neuroinflammation plays a significant role in the progression of frontotemporal dementia (FTD). However, the association between peripheral inflammatory factors and brain neurodegeneration is poorly understood. We aimed to examine changes in peripheral inflammatory markers in patients with behavioural variant FTD (bvFTD) and explore the potential association between peripheral inflammation and brain structure, metabolism, and clinical parameters. Thirty-nine bvFTD patients and 40 healthy controls were enrolled and underwent assessment of plasma inflammatory factors, positron emission tomography/magnetic resonance imaging, and neuropsychological assessments. Group differences were tested using Student's t test, Mann‒Whitney U test, or ANOVA. Partial correlation analysis and multivariable regression analysis were implemented using age and sex as covariates to explore the association between peripheral inflammatory markers, neuroimaging, and clinical measures. The false discovery rate was used to correct for the multiple correlation test. Plasma levels of six factors, including interleukin (IL)-2, IL-12p70, IL-17A, tumour necrosis superfamily member 13B (TNFSF/BAFF), TNFSF12 (TWEAK), and TNFRSF8 (sCD30), were increased in the bvFTD group. Five factors were significantly associated with central degeneration, including IL-2, IL-12p70, IL-17A, sCD30/TNFRSF8, and tumour necrosis factor (TNF)-α; the association between inflammation and brain atrophy was mainly distributed in frontal-limbic-striatal brain regions, whereas the association with brain metabolism was mainly in the frontal-temporal-limbic-striatal regions. BAFF/TNFSF13B, IL-4, IL-6, IL-17A and TNF-α were found to correlate with clinical measures. Peripheral inflammation disturbance in patients with bvFTD participates in disease-specific pathophysiological mechanisms, which could be a promising target for diagnosis, treatment, and monitoring therapeutic efficacy.
2021-09-02 | Isolation and characterization of antibody fragments selective for human FTD brain derived TDP-43 variants.
Frontotemporal dementia (FTD) is the second leading cause of early onset dementia following Alzheimer's disease. It involves atrophy of the frontal and temporal regions of the brain affecting language, memory, and behavior. Transactive response DNA-binding protein 43 (TDP-43) pathology is found in most FTD and ALS cases. It plays a role in transcription, translation and serves as a shuttle between the nucleus and cytoplasm. Prior to its aggregation, TDP-43 exists as polyubiquitinated, hyperphosphorylated C-terminal fragments that correlate well with FTD disease progression. Because of the importance of TDP-43 in these diseases, reagents that can selectively recognize specific toxic TDP variants associated with onset and progression of FTD can be effective diagnostic and therapeutic tools. We utilized a novel atomic force microscopy (AFM) based biopanning protocol to isolate single chain variable fragments (scFvs) from a phage display library that selectively bind TDP variants present in human FTD but not cognitively normal age matched brain tissue. We then used the scFvs (FTD-TDP1 through 5) to probe post-mortem brain tissue and sera samples for the presence of FTD related TDP variants. The scFvs readily selected the FTD tissue and sera samples over age matched controls. The scFvs were used in immunohistochemical analysis of FTD and control brain slices where the reagents showed strong staining with TDP in FTD brain tissue slice. FTD-TDP1, FTD-TDP2, FTD-TDP4 and FTD-TDP5 all protected neuronal cells against FTD TDP induced toxicity suggesting potential therapeutic value. These results show existence of different disease specific TDP variants in FTD individuals. We have identified a panel of scFvs capable of recognizing these disease specific TDP variants in postmortem FTD tissue and sera samples over age matched controls and can thus serve as a biomarker tool.
2019-02-11 | Anti-AMPA GluA3 antibodies in Frontotemporal dementia: a new molecular target.
Frontotemporal Dementia (FTD) is a neurodegenerative disorder mainly characterised by Tau or TDP43 inclusions. A co-autoimmune aetiology has been hypothesised. In this study, we aimed at defining the pathogenetic role of anti-AMPA GluA3 antibodies in FTD. Serum and cerebrospinal fluid (CSF) anti-GluA3 antibody dosage was carried out and the effect of CSF with and without anti-GluA3 antibodies was tested in rat hippocampal neuronal primary cultures and in differentiated neurons from human induced pluripotent stem cells (hiPSCs). TDP43 and Tau expression in hiPSCs exposed to CSF was assayed. Forty-one out of 175 screened FTD sera were positive for the presence of anti-GluA3 antibodies (23.4%). FTD patients with anti-GluA3 antibodies more often presented presenile onset, behavioural variant FTD with bitemporal atrophy. Incubation of rat hippocampal neuronal primary cultures with CSF with anti-GluA3 antibodies led to a decrease of GluA3 subunit synaptic localization of the AMPA receptor (AMPAR) and loss of dendritic spines. These results were confirmed in differentiated neurons from hiPSCs, with a significant reduction of the GluA3 subunit in the postsynaptic fraction along with increased levels of neuronal Tau. In conclusion, autoimmune mechanism might represent a new potentially treatable target in FTD and might open new lights in the disease underpinnings.
2017-04-13 | Poly‐GP in cerebrospinal fluid links C9orf72‐associated dipeptide repeat expression to the asymptomatic phase of ALS/FTD
Abstract The C9orf72 GGGGCC repeat expansion is a major cause of amyotrophic lateral sclerosis and frontotemporal dementia (c9 ALS / FTD ). Non‐conventional repeat translation results in five dipeptide repeat proteins ( DPR s), but their clinical utility, overall significance, and temporal course in the pathogenesis of c9 ALS / FTD are unclear, although animal models support a gain‐of‐function mechanism. Here, we established a poly‐ GP immunoassay from cerebrospinal fluid ( CSF ) to identify and characterize C9orf72 patients. Significant poly‐ GP levels were already detectable in asymptomatic C9orf72 mutation carriers compared to healthy controls and patients with other neurodegenerative diseases. The poly‐ GP levels in asymptomatic carriers were similar to symptomatic c9 ALS / FTD cases. Poly‐ GP levels were not correlated with disease onset, clinical scores, and CSF levels of neurofilaments as a marker for axonal damage. Poly‐ GP determination in CSF revealed a C9orf72 mutation carrier in our cohort and may thus be used as a diagnostic marker in addition to genetic testing to screen patients. Presymptomatic expression of poly‐ GP and likely other DPR species may contribute to disease onset and thus represents an alluring therapeutic target.
other
2026-06-17 | Diagnosis and management of frontotemporal dementia: a narrative review.
Frontotemporal dementia (FTD) is an umbrella term that encompasses a group of clinically heterogeneous neurodegenerative disorders. It is biologically referred to as Frontotemporal lobar degeneration (FTLD) and is characterized by progressive degeneration of frontal and/or temporal lobes. FTD poses substantial diagnostic and therapeutic challenges due to its heterogeneous clinical presentations, limited biomarker specificity, and overlap with other neurodegenerative and psychiatric diseases. This review synthesizes updated knowledge on the clinical phenotypes of FTD, their prognostic elements, and the underlying genetic and molecular mechanisms. Advances in diagnostic strategies are discussed, including structural and functional neuroimaging, fluid biomarkers, and genetic testing, together with emerging digital and AI-assisted tools that may enhance diagnostic precision. Evidence-based management approaches are examined, alongside the role of multidisciplinary care and caregiver support. Promising therapeutic strategies, including gene-targeted interventions, antisense oligonucleotides, progranulin restoration strategies, immunotherapies, and neuromodulation techniques, are discussed considering recent clinical and preclinical developments. Despite the absence of approved disease-modifying therapies, rapid progress in biomarker development, patient stratification, and personalized approaches offers encouraging prospects for more effective interventions across the FTD spectrum. PubMed/MEDLINE was searched for peer-reviewed articles on FTD diagnosis and management; reference lists of key articles were screened to identify additional sources.
2024-03-21 | Distinctive whole-brain cell types predict tissue damage patterns in thirteen neurodegenerative conditions
For over a century, brain research narrative has mainly centered on neuron cells. Accordingly, most neurodegenerative studies focus on neuronal dysfunction and their selective vulnerability, while we lack comprehensive analyses of other major cell types’ contribution. By unifying spatial gene expression, structural MRI, and cell deconvolution, here we describe how the human brain distribution of canonical cell types extensively predicts tissue damage in 13 neurodegenerative conditions, including early- and late-onset Alzheimer’s disease, Parkinson’s disease, dementia with Lewy bodies, amyotrophic lateral sclerosis, mutations in presenilin-1, and 3 clinical variants of frontotemporal lobar degeneration (behavioral variant, semantic and non-fluent primary progressive aphasia) along with associated three-repeat and four-repeat tauopathies and TDP43 proteinopathies types A and C. We reconstructed comprehensive whole-brain reference maps of cellular abundance for six major cell types and identified characteristic axes of spatial overlapping with atrophy. Our results support the strong mediating role of non-neuronal cells, primarily microglia and astrocytes, in spatial vulnerability to tissue loss in neurodegeneration, with distinct and shared across-disorder pathomechanisms. These observations provide critical insights into the multicellular pathophysiology underlying spatiotemporal advance in neurodegeneration. Notably, they also emphasize the need to exceed the current neuro-centric view of brain diseases, supporting the imperative for cell-specific therapeutic targets in neurodegeneration.
2019-10-28 | Behavioral Variant Frontotemporal Dementia as a Serious Complication of Spontaneous Intracranial Hypotension.
Behavioral variant frontotemporal dementia (bvFTD) is a devastating early onset dementia. Symptoms of bvFTD may be caused by spontaneous intracranial hypotension (SIH), a treatable disorder, but no comprehensive study of such patients has been reported. To describe detailed characteristics of a large cohort of patients with SIH and symptoms of bvFTD. We identified patients with SIH who met clinical criteria for bvFTD. Patients were compared to a cohort of SIH patients without bvFTD. The mean age for the 21 men and 8 women was 52.9 yr (range, 37-65 yr). All 29 patients with bvFTD symptoms had hypersomnolence. Magnetic resonance imaging showed brain sagging in all patients, cerebrospinal fluid (CSF) opening pressure low in about half of patients, but a spinal CSF leak could not be detected in any patient. All patients underwent epidural blood patching, but 26 patients eventually underwent 1 or more surgical procedures. Overall, a good outcome was obtained in 21 patients (72%); 20 (91%) of 22 patients who had not undergone prior Chiari surgery compared to 1 (14%) of 7 patients who did undergo Chiari surgery (P < .003). Compared to SIH patients without symptoms of bvFTD (n = 547), those with bvFTD symptoms were older, more often male, less often demonstrated CSF leak on spinal imaging, and more often underwent surgery (P < .02). bvFTD in SIH is rare and associated with brain sagging and hypersomnolence. Spinal CSF leaks are rarely detected. bvFTD symptoms are often refractory to the usual percutaneous procedures but most patients can be cured.
2019-01-15 | Molecular Mechanisms of Neurodegeneration Related to C9orf72 Hexanucleotide Repeat Expansion.
Two clinically distinct diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), have recently been classified as two extremes of the FTD/ALS spectrum. The neuropathological correlate of FTD is frontotemporal lobar degeneration (FTLD), characterized by tau-, TDP-43-, and FUS-immunoreactive neuronal inclusions. An earlier discovery that a hexanucleotide repeat expansion mutation in chromosome 9 open reading frame 72 ( C9orf72 ) gene causes ALS and FTD established a special subtype of ALS and FTLD with TDP-43 pathology (C9FTD/ALS). Normal individuals carry 2–10 hexanucleotide GGGGCC repeats in the C9orf72 gene, while more than a few hundred repeats represent a risk for ALS and FTD. The proposed molecular mechanisms by which C9orf72 repeat expansions induce neurodegenerative changes are C9orf72 loss-of-function through haploinsufficiency, RNA toxic gain-of-function, and gain-of-function through the accumulation of toxic dipeptide repeat proteins. However, many more cellular processes are affected by pathological processes in C9FTD/ALS, including nucleocytoplasmic transport, RNA processing, normal function of nucleolus, formation of membraneless organelles, translation, ubiquitin proteasome system, Notch signalling pathway, granule transport, and normal function of TAR DNA-binding protein 43 (TDP-43). Although the exact molecular mechanisms through which C9orf72 repeat expansions account for neurodegeneration have not been elucidated, some potential therapeutics, such as antisense oligonucleotides targeting hexanucleotide GGGGCC repeats in mRNA, were successful in preclinical trials and are awaiting phase 1 clinical trials. In this review, we critically discuss each proposed mechanism and provide insight into the most recent studies aiming to elucidate the molecular underpinnings of C9FTD/ALS.
2018-04-10 | Auto-antibodies against P/Q- and N-type voltage-dependent calcium channels mimicking frontotemporal dementia
The behavioral variant of frontotemporal dementia is usually a sporadic and progressive neurodegenerative disorder. Here, we report the subacute onset of a frontotemporal dementia phenotype with a treatable etiology. The patient has a history of rheumatoid arthritis, episcleritis, and thyroid eye disease on immunosuppressive therapy. He experienced a rapid personality change, including inappropriate behavior, which suggested frontotemporal dementia. Results of imaging and neuropsychological testing also suggested frontotemporal dementia. Because of his autoimmune diseases and unusually short onset of symptoms, serum paraneoplastic panel and cerebrospinal fluid were analyzed and revealed elevated P/Q- and N-type calcium channel antibodies. Treatment with therapeutic plasma exchange resulted in a rapid improvement of his behavior and cognition. This case suggests that there may be some treatable causes of frontotemporal dementia symptomatology, that is, paraneoplastic antibodies. In the context of atypical features of frontotemporal dementia, practitioners should maintain a high index of suspicion.
proteins
2026-04-02 | Peripheral immune profiling in frontotemporal dementia.
Frontotemporal dementia (FTD) encompasses a heterogenous and clinically diverse group of disorders, including the behavioural variant frontotemporal dementia, the non-fluent and the semantic variants of primary progressive aphasia. While these subtypes present with distinct clinical features, emerging evidence implicates neuroinflammation as a shared pathogenic mechanism. Nevertheless, little is known regarding the status of the peripheral immune system in the pathogenesis of FTD. Blood samples were obtained from 27 individuals with a clinical diagnosis of FTD (7 behavioural variants FTD, 10 non-fluent and 10 semantic variants of primary progressive aphasia) and 25 age-matched healthy controls. The immunophenotypes of peripheral immune cell populations were assessed with multicolour flow cytometry. Regulatory T cells were isolated and co-cultured with responder T cells and proliferation was determined by 3H-thymidine incorporation. The immune-related transcriptomic profile of isolated monocytes was analysed using the NanoString Human Inflammation Panel. Plasma levels of inflammatory cytokines and chemokines were quantified using the Olink® Target 48 Cytokine panel. Our analysis demonstrated that the suppressive function of regulatory T cells on responder T cells proliferation was significantly compromised in FTD individuals compared to healthy controls (P < 0.05). Transcriptomic profiling of FTD monocytes revealed a potential dysregulation of 153 immune-related genes. Enrichment analysis showed that these genes were mainly involved in chemokine-mediated signalling pathway, monocyte and lymphocyte chemotaxis, response to interferon-gamma and positive regulation of ERK1 and ERK2 cascades. Proteomic analysis of plasma inflammatory mediators showed a significant increase in the pro-inflammatory cytokine TNFa (P < 0.05) and the chemokines CXCL10, CCL3, CCL19, CSF1 (P < 0.05) and CXCL12 (P < 0.01) in FTD individuals compared to healthy controls. These findings provide the first evidence that the immunomodulatory function of regulatory T cells is compromised in individuals with FTD. In addition, there is a dysregulation of inflammation-related gene expression in peripheral monocytes and an increase of plasma inflammatory chemokines and cytokines in FTD individuals. Further investigation is warranted to assess the therapeutic potential of restoring dysfunctional regulatory T cells and modulating the inflammatory profile in the clinical setting of FTD.
2026-02-18 | Breaking β-sheets in FUS prion-like domain preserves phase separation and function but prevents aggregation and toxicity
Abstract The RNA-binding protein Fused in Sarcoma (FUS) undergoes phase separation associated with RNA processing. However, the prion-like low complexity (LC) domain of FUS forms solid-like aggregates in neurodegenerative diseases. Whether the formation of β-sheet structure associated with pathology is also physiologically/functionally relevant is debated. Similarly, if mislocalization alone or concomitant aggregation is responsible for FUS gain-of-function toxicity remains to be probed. Here, we introduce β-sheet breaking proline residues into FUS LC with the goal of preventing cross-β-driven aggregation without disrupting essential functions and phase separation. β-sheet-deficient FUS variants maintain native-like global motions, disorder, and phase separation, but no longer show a liquid-to-solid transition (LST). Biochemical partitioning, cellular localization, and auto- and cross-regulatory functions of FUS all remain essentially unchanged. Conversely, FUS-induced neurodegeneration in several Drosophila models is drastically reduced. These findings suggest a strategy for mitigating disease-related toxicity through backbone structure modulation to prevent prion-like domain protein aggregation. GRAPHICAL ABSTRACT SUMMARY The RNA-binding protein Fused in Sarcoma (FUS) undergoes phase separation as part of its physiological function but can aberrantly aggregate into solid-like assemblies in amyotrophic lateral sclerosis and frontotemporal dementia. To dissect the role of β-sheets in both function and pathological transition, we engineered β-sheet-preventing FUS variants via targeted proline residue insertions in the prion-like disordered region. These variants retained native structure, motions, and phase behavior yet showed dramatically reduced aggregation, both as an isolated prion-like domain and in full-length FUS. Crucially, these variants maintained a panel of FUS cellular functions that depend on FUS condensation but prevented FUS toxicity in fly models of neurodegeneration. Our findings implicate β-sheets as key drivers of FUS condensate maturation and neuronal toxicity, highlighting β-sheet modulation as a therapeutic strategy against FUS-related neurodegeneration. HIGHLIGHTS Targeted proline additions disrupt β-sheet formation in FUS without altering native conformations, dynamics, or phase separation behavior β-sheet-deficient FUS variants prevent aggregation and liquid-to-solid transitions while retaining key biological functions In vivo models reveal attenuated toxicity of β-sheet-deficient FUS in Drosophila β-sheets are identified as central drivers of condensate maturation and neuronal death, offering a therapeutic entry point for modulating prion-like domain pathology
2025-11-22 | Multiplex neurodegeneration proteotoxicity platform reveals DNAJB6 promotes non-toxic FUS condensate gelation and inhibits neurotoxicity.
Neurodegenerative disorders (NDDs) are a family of diseases that remain poorly treated despite their growing global health burden. To gain insight into the mechanisms and modulators of neurodegeneration, we developed a yeast-based multiplex genetic screening platform. Using this platform, 32 NDD-associated proteins are probed against a library of 132 molecular chaperones from both yeast and humans, and an unbiased set of ~900 human proteins. We identify both broadly active and specific modifiers of our various cellular models. To illustrate the translatability of this platform, we extensively characterize a potent hit from our screens, the human chaperone DNAJB6. We show that DNAJB6 modifies the toxicity and solubility of multiple amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD)-linked RNA-binding proteins (RBPs). Biophysical examination of DNAJB6 demonstrated that it co-phase separates with, and alters the behavior of FUS containing condensates by locking them into a loose gel-like state which prevents their fibrilization. Domain mapping and a deep mutational scan of DNAJB6 revealed key residues required for its activity and identified variants with enhanced activity. Finally, we show that overexpression of DNAJB6 prevents motor neuron loss and the associated microglia activation in a mouse model of FUS-ALS.
2023-12-01 | ABCA7 Mutations Can Present as Behavioral Variant Frontotemporal Dementia Without Amyloid Pathology
Abstract Background ABCA7 was identified as an Alzheimer’s disease (AD) risk gene in 2011 through GWAS studies and subsequently its role in pathogenesis was confirmed via in‐vivo studies demonstrating loss of ABCA7 was sufficient to the trigger amyloid cascade. The most common presentation of ABCA7 loss of function mutations is an amnestic syndrome, however it less commonly can present with behavioral or motor symptoms. While the described clinical presentation can vary, almost all cases have been associated with AD pathology. Here we present three cases of bvFTD clinical syndromes in ABCA7 mutations carriers without evidence of AD pathology. Method Patients underwent a comprehensive clinical assessment including neurological history, examination, neuropsychological testing, MR brain imaging, and lumbar puncture. AD biomarkers were assessed through CSF testing. Genetic testing was obtained through CLIA certified whole genome sequencing. Result We identified three individuals with mutations in ABCA7 . Two of these individuals harbor the p.I1878M mutation and one with the p.W1214* mutation on genetic testing. They presented with behavioral variant frontotemporal dementia with no evidence of amyloid pathology on CSF biomarker testing. Conclusion We present three cases of symptomatic ABCA7 mutation carriers without evidence of underlying AD pathology. The exact function of ABCA7 is unknown, however its purported involvement in lipid transport and immune responses are common pathways in neurodegenerative disease and raises the possibility of converging disease cascades.
2023-10-23 | Anterior cingulate sulcation is associated with onset and survival in frontotemporal dementia.
Frontotemporal dementia is the second most common form of early onset dementia (<65 years). Despite this, there are few known disease-modifying factors. The anterior cingulate is a focal point of pathology in behavioural variant frontotemporal dementia. Sulcation of the anterior cingulate is denoted by the presence of a paracingulate sulcus, a tertiary sulcus developing, where present during the third gestational trimester and remaining stable throughout life. This study aims to examine the impact of right paracingulate sulcal presence on the expression and prognosis of behavioural variant frontotemporal dementia. This retrospective analysis drew its population from two clinical samples recruited from memory clinics at university hospitals in the USA and The Netherlands. Individuals with sporadic behavioural variant frontotemporal dementia were enrolled between 2000 and 2022 and followed up for an average of 7.71 years. T1-MRI data were evaluated for hemispheric paracingulate sulcal presence in accordance with an established protocol by two blinded raters. Outcome measures included age at onset, survival, cortical thickness and Frontotemporal Lobar Degeneration-modified Clinical Dementia Rating determined clinical disease progression. The study population consisted of 186 individuals with sporadic behavioural variant frontotemporal dementia (113 males and 73 females), mean age 63.28 years (SD 8.32). The mean age at onset was 2.44 years later in individuals possessing a right paracingulate sulcus [60.2 years (8.54)] versus individuals who did not [57.76 (8.05)], 95% confidence interval > 0.41, P = 0.02. Education was not associated with age at onset (β = -0.05, P = 0.75). The presence of a right paracingulate sulcus was associated with an 83% increased risk of death per year after age at onset (hazard ratio 1.83, confidence interval [1.09-3.07], P < 0.02), whilst the mean age at death was similar for individuals with a present and absent right paracingulate sulcus (P = 0.7). Right paracingulate sulcal presence was not associated with baseline cortical thickness. Right paracingulate sulcal presence is associated with disease expression and survival in sporadic behavioural variant frontotemporal dementia. Findings provide evidence of neurodevelopmental brain reserve in behavioural variant frontotemporal dementia that may be important in the design of trials for future therapeutic approaches.
gene therapies
2026-04-29 | Humanized mice carrying a pathogenic GRN deletion as a pre-clinical platform for targeted gene therapies in frontotemporal dementia.
Frontotemporal dementia (FTD) is an early onset dementia characterized by neuropathology and changes to patient behaviour. Haploinsufficiency of the gene progranulin (GRN) is a major cause of FTD, for which there are no effective therapies. Corrective gene therapies that restore GRN expression are of clinical interest, but current in vivo systems have limitations. We developed a novel strain of mice expressing a human GRN transgene bearing a four base pair deletion in exon 5 (GRNc.388_391delCAGT) that causes FTD. Characterization of mice expressing the mutant transgene (GRNmEx5) indicates that GRNmEx5 is expressed at low levels and retains partial function. The GRNmEx5 protein partially rescues progranulin nullizygous-associated neuropathology and transcriptomic dysfunction. Following characterization, we sought to determine if mice expressing GRNmEx5 in the absence of mouse progranulin (Grn-/-; GRNmEx5 mice) could enable pre-clinical gene therapy development. Using CRISPR/Cas9 with lipid nanoparticle delivery, we achieved 8.5% correction of GRNc.388_391delCAGT in target cells in Grn-/-; GRNmEx5 mice, demonstrating both effective in vivo homology-directed repair and the utility of Grn-/-; GRNmEx5 mice for developing novel progranulin-associated FTD therapies. The Grn-/-; GRNmEx5 model provides insight into progranulin biology, increases our understanding of a pathogenic variant that causes FTD, and facilitates the development of GRN gene therapies.
2024-11-01 | Genetics of Frontotemporal Dementia: an updated overview
Frontotemporal dementia (FTD) involves a category of disorders characterized by behavioral, linguistic, and mobility abnormalities resulting from neurodegeneration in the frontal and temporal lobes. FTD represents the second most common etiology of early-onset dementia, and is distinguished by a wide range of clinical features. Indeed, three clinical variants are well known: the behavioral variant (bvFTD), which is the most prevalent and predominantly associated with personality and behavioral changes, the semantic variant primary progressive aphasia (svPPA), which is associated with gradual loss of speech integrity and word meaning, and the non-fluent variant primary progressive aphasia (nfvPPA), in which patients have difficulties getting words out, with slurred speech and an abnormal voice. About 15% of FTD patients also have another neurodegenerative motor neuron disease, amyotrophic lateral sclerosis (ALS), and this co-occurrence is called FTD-ALS. About half of FTD cases are familial. The most common observed mode of inheritance for familial FTD is autosomal dominant. So far, at least ten causal genes have been implicated in the etiology of FTD. Three of these genes: the microtubule-associated protein tau (MAPT), progranulin (GRN) and chromosome 9 open reading frame 72 (C9ORF72), are the most common and are responsible for more than half of familial FTD. The remaining genes are rarely reported, and the pathological mechanisms of many of them are unclear. The causes of the remainder of the familial FTD proportion, as well as the sporadic FTD, are to be determined. We conclude that despite all the breakthroughs in discovering the etiology of FTD, the majority of work is still to be done. The discovered causal FTD genes give insights toward a better understanding of the clinical and genetic heterogeneity of FTD, and help in its early and correct diagnosis. Despite the current management of FTD relies mainly on supportive treatment several promising clinical trials showed promising results in the correction of the harmful effects caused by the mutant genes.
2024-06-05 | Peripheral expression of brain-penetrant progranulin rescues pathologies in mouse models of frontotemporal lobar degeneration.
Progranulin (PGRN) haploinsufficiency is a major risk factor for frontotemporal lobar degeneration with TAR DNA-binding protein 43 (TDP-43) pathology (FTLD-GRN). Multiple therapeutic strategies are in clinical development to restore PGRN in the CNS, including gene therapy. However, a limitation of current gene therapy approaches aimed to alleviate FTLD-associated pathologies may be their inefficient brain exposure and biodistribution. We therefore developed an adeno-associated virus (AAV) targeting the liver (L) to achieve sustained peripheral expression of a transferrin receptor (TfR) binding, brain-penetrant (b) PGRN variant [AAV(L):bPGRN] in two mouse models of FTLD-GRN, namely, Grn knockout and GrnxTmem106b double knockout mice. This therapeutic strategy avoids potential safety and biodistribution issues of CNS-administered AAVs and maintains sustained concentrations of PGRN in the brain after a single dose. AAV(L):bPGRN treatment reduced several FTLD-GRN-associated pathologies including severe motor function deficits, aberrant TDP-43 phosphorylation, dysfunctional protein degradation, lipid metabolism, gliosis, and neurodegeneration in the brain. The potential translatability of our findings was tested in an in vitro model using cocultured human induced pluripotent stem cell (hiPSC)-derived microglia lacking PGRN and TMEM106B and wild-type hiPSC-derived neurons. As in mice, aberrant TDP-43, lysosomal dysfunction, and neuronal loss were ameliorated after treatment with exogenous TfR-binding protein transport vehicle fused to PGRN (PTV:PGRN). Together, our studies suggest that peripherally administered brain-penetrant PGRN replacement strategies ameliorate FTLD-GRN relevant phenotypes including TDP-43 pathology, neurodegeneration, and behavioral deficits. Our data provide preclinical proof of concept for the use of this AAV platform for treatment of FTLD-GRN and potentially other CNS disorders.
2024-01-16 | Characterization of Progranulin Gene Mutations in Portuguese Patients with Frontotemporal Dementia.
In Portugal, heterozygous loss-of-function mutations in the progranulin (GRN) gene account for approximately half of the genetic mediated forms of frontotemporal dementia (FTD). GRN mutations reported thus far cause FTD through a haploinsufficiency disease mechanism. Herein, we aim to unveil the GRN mutation spectrum, investigated in 257 FTD patients and 19 family members from the central/north region of Portugal using sequencing methods. Seven different pathogenic variants were identified in 46 subjects including 40 patients (16%) and 6 relatives (32%). bvFTD was the most common clinical presentation among the GRN mutation patients, who showed a global pattern of moderate-to-severe frontotemporoparietal deficits in the neuropsychological evaluation. Interestingly, two mutations were novel (p.Thr238Profs*18, p.Leu354Profs*16), and five were previously described, although three of them only in the Portuguese population, suggesting a population-specific GRN mutational spectrum. The subjects harboring a GRN mutation showed a significant reduction in serum PGRN levels, supporting the pathogenic nature of these variants. This work broadens the mutation spectrum of GRN and the identification of the underlying GRN mutations provided an accurate genetic counselling and allowed the enrolment of subjects with GRN mutations (both asymptomatic and symptomatic) in ongoing clinical trials, which is essential to test new drugs for the disease.
2021-11-10 | Neuropathological and behavioral characterization of aged Grn R493X progranulin-deficient frontotemporal dementia knockin mice.
Frontotemporal lobar degeneration (FTLD) causes a spectrum of clinical presentations of frontotemporal dementia (FTD), including progressive changes in behavior, personality, executive function, and language. Up to 20% of familial FTLD cases are caused by progranulin (GRN) haploinsufficiency (FTD-GRN), with one of the most common causal variant being a nonsense mutation at arginine 493 (R493X). Recently, a genetic knockin FTD-GRN mouse model was generated bearing this GrnR493X mutation, at the analogous arginine in murine Grn. Aged, homozygous GrnR493X mice (GrnR493X/R493X) have been shown to phenotypically replicate several neuropathological hallmarks previously demonstrated in Grn null mice. We conducted a comprehensive neuropathological and behavioral assessment of 18 month old GrnR493X/R493X mice, observing a striking lysosomal dysfunction and thalamic neurodegeneration not previously described in this model, as well as a male-specific increase in generalized anxiety. These findings provide additional phenotypic markers of pathogenesis in aged GrnR493X/R493X mice that will contribute to better defining mechanisms underlying FTD-GRN, and offer relevant outcome measures for preclinical efficacy testing of novel therapeutics that target nonsense mutations leading to this devastating disease.
small molecules
2026-08-22 | Language impairments in behavioural variant frontotemporal dementia: a comparative study with semantic dementia.
Recent evidence suggests that individuals with behavioural variant frontotemporal dementia (bvFTD) may experience language changes in a similar, but less severe manner, than what is observed in semantic dementia (SD). Few studies, however, have specifically compared these patient groups or considered the cognitive underpinnings. To explore this in more depth, this study aimed to profile patterns of language performance within both "probable" and "possible" categories of bvFTD and to compare them to SD, while also considering the relationships between language and executive function measures. Participants included 106 probable bvFTD, 43 possible bvFTD, 42 SD, and 112 healthy controls from the FRONTIER clinic. Data analysed included the Addenbrooke's Cognitive Examination (ACE-III), single word processing (SYDBAT) and executive function measures (word generativity, mental flexibility, response inhibition and working memory). Naming and semantic association impairments frequently occurred in probable bvFTD (51% and 49% respectively). Approximately one quarter of possible bvFTD patients also showed language impairments. The SD pattern of pronounced naming impairment as compared to other single word tasks, was not found in the bvFTD groups. Semantic measures from the ACE-III predicted language performance in bvFTD groups; response initiation and suppression also emerged as a significant predictor. Naming and semantic association deficits commonly arise in probable bvFTD, but may also be observed in some patients with possible bvFTD. The pattern of impairments in bvFTD were not wholly consistent with those seen in SD. Both semantic and executive function measures may be associated with language performance deficits observed in bvFTD.
2026-07-29 | Single-cell transcriptomic atlas of frontoinsular cortex reveals molecular correlates of selective neuronal vulnerability in FTD.
Frontotemporal dementia (FTD) is characterized by selective neuronal vulnerability, yet the features that predispose specific neuron types to degeneration remain unclear. We performed single-nucleus RNA sequencing of frontoinsular cortex, a region affected early in behavioral variant FTD, across individuals with C9orf72-associated and sporadic FTD-MND spectrum disease. By enriching for large projection neurons, we resolved molecular subtypes of layer 5 extratelencephalic neurons, including von Economo neurons, and identified selective depletion of specific layer 2/3 and layer 5 neuron subtypes, convergent across genotypes. Despite selective neuronal loss, disease-associated transcriptional changes were convergent across excitatory neuron populations, suggesting that they reflect upstream pathophysiology or shared responses to local neurodegeneration. By relating neighborhood-level depletion in disease to gene expression in controls, we found that baseline cellular respiration and ATP synthesis predict neuronal vulnerability in disease. These findings define molecular correlates of selective neuronal vulnerability in FTD and provide a framework linking cell type and state to neurodegeneration.
2026-07-16 | Survival estimates and their predictors in genetic frontotemporal dementia: an international, retrospective, cohort study.
What drives the heterogeneity of survival estimates in genetic frontotemporal dementia is unknown. We sought to understand the natural history and predictors of disease trajectory, which are crucial not only for effective care but also for the design of therapeutic clinical trials and efficacy evaluation. In this international, cohort study, we used the Kaplan-Meier method to retrospectively assess survival estimates in patients enrolled in the GENFI cohort, which included 32 research sites located in Belgium, Canada, Finland, France, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, and the UK, and comprised participants carrying a causal C9orf72 expansion or a causal mutation in GRN or MAPT genes. Survival was calculated as the time from symptom onset to time of death or censoring date; median survival estimate for all patients was the primary endpoint. Cox proportional hazards models were used to identify predictors of survival, which were subsequently externally validated in an independent cohort. We further designed a structural equation model to assess the relationships between predictors, applying a least absolute shrinkage and selection operator method. Of 278 participants of the GENFI cohort included in this study, 160 (58%) were men and 118 (42%) were women. 162 died during follow-up (58%) and 116 were still alive (42%) on June 1, 2024, the chosen censoring date. 138 participants carried a C9orf72 expansion, 94 carried a GRN mutation, and 46 a MAPT mutation. 179 participants were diagnosed with behavioural variant frontotemporal dementia, 46 with primary progressive aphasia, and 31 with frontotemporal dementia-amyotrophic lateral sclerosis. 22 participants had other diagnoses. The median survival estimate for all patients with genetic frontotemporal dementia was 6·94 years (95% CI 6·59-7·80) from symptom onset. The median survival estimate for patients with GRN mutations was 6·63 years (6·08-7·98), for patients with a C9orf72 expansion was 7·04 years (6·45-8·77), and for patients with MAPT mutations was 8·56 years (7·06-13·50). Older age at onset, shorter disease duration from onset to enrolment in the GENFI study, clinical presentation (ie, frontotemporal dementia-amyotrophic lateral sclerosis), domain of first symptom (ie, motor or language onset), and geographical area of residency (ie, central and southern Europe) were associated with poorer prognosis. Genetic group did not directly affect survival estimates; rather its effect was mediated by age at onset and clinical phenotype. We computed a genetic frontotemporal dementia survival risk index, which can be used at an individual patient level. Our results highlight that motor impairment in addition to cognitive and behavioural symptoms should be considered when estimating prognosis in genetic frontotemporal dementia. Individual risk scores might be of help for patient stratification in future therapeutic trials, although refinement and prospective validation are now needed. Italian Ministry of Health (Ricerca Corrente), Fondation Philippe Chatrier, and Fondation Vaincre Alzheimer.
2026-06-29 | Associations of local white matter geometry with network efficiency, macrostructural abnormalities, and clinical severity in behavioural variant frontotemporal dementia.
Behavioural variant frontotemporal dementia (bvFTD), marked by profound changes in behaviour and personality, is the most common subtype of frontotemporal dementia, driven by neurodegeneration in frontotemporal regions. This neurodegeneration pattern is partially shaped by white matter abnormalities arising from the spread of protein aggregates along axonal pathways. While prior studies mainly focused on diffusion tensor imaging metrics such as fractional anisotropy and mean diffusivity, the alteration in local white matter geometry remains largely unexplored. Using a novel Director Field Analysis (DFA) method, 51 patients with bvFTD and 51 healthy controls were studied to examine alterations in the local geometry of white matter fibres in bvFTD, and their associations with macrostructural morphology, global network parameters, and clinical manifestations. Unlike the unidirectional decrease in fractional anisotropy and increase in mean diffusivity, we identified significant bidirectional alterations in white matter local geometry, characterized by increased geometric distortion in the forceps minor and dorsal cingulum and decreased distortion in widespread frontotemporal association tracts, including the inferior fronto-occipital fasciculus, superior longitudinal fasciculus, uncinate fasciculus, frontal aslant tract, and arcuate fasciculus. Patients with bvFTD also showed reduced cerebral white and grey matter volumes (both P < 0.0026), enlarged lateral ventricles and choroid plexus (both P < 0.0001), decreased global network efficiency (P = 0.0010), and increased local efficiency (P = 0.0014). Importantly, decreased white matter geometric distortion across affected tracts was strongly associated with greater clinical severity, as reflected by higher Clinical Dementia Rating scores (r = -0.68, P < 0.0001). Mediation analyses further demonstrated that white matter geometric distortion significantly mediated the effects of macrostructural atrophy and reduced global network efficiency on clinical severity. Furthermore, neuroimaging-transcriptional association analysis on the group differences in nodal efficiency of the white matter networks identified several biological processes/pathways critical for the formation and propagation of TAR-DNA-binding protein 43/microtubule-associated protein tau pathologies along axonal pathways, as well as processes related to cellular homeostasis and oligodendrocyte-related pathways that may exacerbate these proteinopathies. Our findings advance understanding of the neural bases of the functional impairments in bvFTD and suggest potential mechanistic pathways for developing novel treatment strategies.
2026-06-09 | Obsessive-compulsive Symptomatology and Caudate Tau Burden in Autopsy-confirmed FTLD-tau (P9-13.003)
To examine the relationship between obsessive-compulsive symptoms and caudate tau pathology in behavioral variant frontotemporal dementia (bvFTD) and primary progressive aphasia (PPA) due to frontotemporal lobar degeneration with tau pathology (FTLD-tau).
antibodies
2023-08-03 | Microglial activation in the frontal cortex predicts cognitive decline in frontotemporal dementia.
Frontotemporal dementia is clinically and neuropathologically heterogeneous, but neuroinflammation, atrophy and cognitive impairment occur in all of its principal syndromes. Across the clinical spectrum of frontotemporal dementia, we assess the predictive value of in vivo neuroimaging measures of microglial activation and grey-matter volume on the rate of future cognitive decline. We hypothesized that inflammation is detrimental to cognitive performance, in addition to the effect of atrophy. Thirty patients with a clinical diagnosis of frontotemporal dementia underwent a baseline multimodal imaging assessment, including [11C]PK11195 PET to index microglial activation and structural MRI to quantify grey-matter volume. Ten people had behavioural variant frontotemporal dementia, 10 had the semantic variant of primary progressive aphasia and 10 had the non-fluent agrammatic variant of primary progressive aphasia. Cognition was assessed at baseline and longitudinally with the revised Addenbrooke's Cognitive Examination, at an average of 7-month intervals (for an average of ∼2 years, up to ∼5 years). Regional [11C]PK11195 binding potential and grey-matter volume were determined, and these were averaged within four hypothesis-driven regions of interest: bilateral frontal and temporal lobes. Linear mixed-effect models were applied to the longitudinal cognitive test scores, with [11C]PK11195 binding potentials and grey-matter volumes as predictors of cognitive performance, with age, education and baseline cognitive performance as covariates. Faster cognitive decline was associated with reduced baseline grey-matter volume and increased microglial activation in frontal regions, bilaterally. In frontal regions, microglial activation and grey-matter volume were negatively correlated, but provided independent information, with inflammation the stronger predictor of the rate of cognitive decline. When clinical diagnosis was included as a factor in the models, a significant predictive effect was found for [11C]PK11195 BPND in the left frontal lobe (-0.70, P = 0.01), but not for grey-matter volumes (P > 0.05), suggesting that inflammation severity in this region relates to cognitive decline regardless of clinical variant. The main results were validated by two-step prediction frequentist and Bayesian estimation of correlations, showing significant associations between the estimated rate of cognitive change (slope) and baseline microglial activation in the frontal lobe. These findings support preclinical models in which neuroinflammation (by microglial activation) accelerates the neurodegenerative disease trajectory. We highlight the potential for immunomodulatory treatment strategies in frontotemporal dementia, in which measures of microglial activation may also improve stratification for clinical trials.
2023-03-10 | Peripheral inflammation in behavioural variant frontotemporal dementia: associations with central degeneration and clinical measures.
Neuroinflammation plays a significant role in the progression of frontotemporal dementia (FTD). However, the association between peripheral inflammatory factors and brain neurodegeneration is poorly understood. We aimed to examine changes in peripheral inflammatory markers in patients with behavioural variant FTD (bvFTD) and explore the potential association between peripheral inflammation and brain structure, metabolism, and clinical parameters. Thirty-nine bvFTD patients and 40 healthy controls were enrolled and underwent assessment of plasma inflammatory factors, positron emission tomography/magnetic resonance imaging, and neuropsychological assessments. Group differences were tested using Student's t test, Mann‒Whitney U test, or ANOVA. Partial correlation analysis and multivariable regression analysis were implemented using age and sex as covariates to explore the association between peripheral inflammatory markers, neuroimaging, and clinical measures. The false discovery rate was used to correct for the multiple correlation test. Plasma levels of six factors, including interleukin (IL)-2, IL-12p70, IL-17A, tumour necrosis superfamily member 13B (TNFSF/BAFF), TNFSF12 (TWEAK), and TNFRSF8 (sCD30), were increased in the bvFTD group. Five factors were significantly associated with central degeneration, including IL-2, IL-12p70, IL-17A, sCD30/TNFRSF8, and tumour necrosis factor (TNF)-α; the association between inflammation and brain atrophy was mainly distributed in frontal-limbic-striatal brain regions, whereas the association with brain metabolism was mainly in the frontal-temporal-limbic-striatal regions. BAFF/TNFSF13B, IL-4, IL-6, IL-17A and TNF-α were found to correlate with clinical measures. Peripheral inflammation disturbance in patients with bvFTD participates in disease-specific pathophysiological mechanisms, which could be a promising target for diagnosis, treatment, and monitoring therapeutic efficacy.
2021-09-02 | Isolation and characterization of antibody fragments selective for human FTD brain derived TDP-43 variants.
Frontotemporal dementia (FTD) is the second leading cause of early onset dementia following Alzheimer's disease. It involves atrophy of the frontal and temporal regions of the brain affecting language, memory, and behavior. Transactive response DNA-binding protein 43 (TDP-43) pathology is found in most FTD and ALS cases. It plays a role in transcription, translation and serves as a shuttle between the nucleus and cytoplasm. Prior to its aggregation, TDP-43 exists as polyubiquitinated, hyperphosphorylated C-terminal fragments that correlate well with FTD disease progression. Because of the importance of TDP-43 in these diseases, reagents that can selectively recognize specific toxic TDP variants associated with onset and progression of FTD can be effective diagnostic and therapeutic tools. We utilized a novel atomic force microscopy (AFM) based biopanning protocol to isolate single chain variable fragments (scFvs) from a phage display library that selectively bind TDP variants present in human FTD but not cognitively normal age matched brain tissue. We then used the scFvs (FTD-TDP1 through 5) to probe post-mortem brain tissue and sera samples for the presence of FTD related TDP variants. The scFvs readily selected the FTD tissue and sera samples over age matched controls. The scFvs were used in immunohistochemical analysis of FTD and control brain slices where the reagents showed strong staining with TDP in FTD brain tissue slice. FTD-TDP1, FTD-TDP2, FTD-TDP4 and FTD-TDP5 all protected neuronal cells against FTD TDP induced toxicity suggesting potential therapeutic value. These results show existence of different disease specific TDP variants in FTD individuals. We have identified a panel of scFvs capable of recognizing these disease specific TDP variants in postmortem FTD tissue and sera samples over age matched controls and can thus serve as a biomarker tool.
2019-02-11 | Anti-AMPA GluA3 antibodies in Frontotemporal dementia: a new molecular target.
Frontotemporal Dementia (FTD) is a neurodegenerative disorder mainly characterised by Tau or TDP43 inclusions. A co-autoimmune aetiology has been hypothesised. In this study, we aimed at defining the pathogenetic role of anti-AMPA GluA3 antibodies in FTD. Serum and cerebrospinal fluid (CSF) anti-GluA3 antibody dosage was carried out and the effect of CSF with and without anti-GluA3 antibodies was tested in rat hippocampal neuronal primary cultures and in differentiated neurons from human induced pluripotent stem cells (hiPSCs). TDP43 and Tau expression in hiPSCs exposed to CSF was assayed. Forty-one out of 175 screened FTD sera were positive for the presence of anti-GluA3 antibodies (23.4%). FTD patients with anti-GluA3 antibodies more often presented presenile onset, behavioural variant FTD with bitemporal atrophy. Incubation of rat hippocampal neuronal primary cultures with CSF with anti-GluA3 antibodies led to a decrease of GluA3 subunit synaptic localization of the AMPA receptor (AMPAR) and loss of dendritic spines. These results were confirmed in differentiated neurons from hiPSCs, with a significant reduction of the GluA3 subunit in the postsynaptic fraction along with increased levels of neuronal Tau. In conclusion, autoimmune mechanism might represent a new potentially treatable target in FTD and might open new lights in the disease underpinnings.
2017-04-13 | Poly‐GP in cerebrospinal fluid links C9orf72‐associated dipeptide repeat expression to the asymptomatic phase of ALS/FTD
Abstract The C9orf72 GGGGCC repeat expansion is a major cause of amyotrophic lateral sclerosis and frontotemporal dementia (c9 ALS / FTD ). Non‐conventional repeat translation results in five dipeptide repeat proteins ( DPR s), but their clinical utility, overall significance, and temporal course in the pathogenesis of c9 ALS / FTD are unclear, although animal models support a gain‐of‐function mechanism. Here, we established a poly‐ GP immunoassay from cerebrospinal fluid ( CSF ) to identify and characterize C9orf72 patients. Significant poly‐ GP levels were already detectable in asymptomatic C9orf72 mutation carriers compared to healthy controls and patients with other neurodegenerative diseases. The poly‐ GP levels in asymptomatic carriers were similar to symptomatic c9 ALS / FTD cases. Poly‐ GP levels were not correlated with disease onset, clinical scores, and CSF levels of neurofilaments as a marker for axonal damage. Poly‐ GP determination in CSF revealed a C9orf72 mutation carrier in our cohort and may thus be used as a diagnostic marker in addition to genetic testing to screen patients. Presymptomatic expression of poly‐ GP and likely other DPR species may contribute to disease onset and thus represents an alluring therapeutic target.
other
2026-06-17 | Diagnosis and management of frontotemporal dementia: a narrative review.
Frontotemporal dementia (FTD) is an umbrella term that encompasses a group of clinically heterogeneous neurodegenerative disorders. It is biologically referred to as Frontotemporal lobar degeneration (FTLD) and is characterized by progressive degeneration of frontal and/or temporal lobes. FTD poses substantial diagnostic and therapeutic challenges due to its heterogeneous clinical presentations, limited biomarker specificity, and overlap with other neurodegenerative and psychiatric diseases. This review synthesizes updated knowledge on the clinical phenotypes of FTD, their prognostic elements, and the underlying genetic and molecular mechanisms. Advances in diagnostic strategies are discussed, including structural and functional neuroimaging, fluid biomarkers, and genetic testing, together with emerging digital and AI-assisted tools that may enhance diagnostic precision. Evidence-based management approaches are examined, alongside the role of multidisciplinary care and caregiver support. Promising therapeutic strategies, including gene-targeted interventions, antisense oligonucleotides, progranulin restoration strategies, immunotherapies, and neuromodulation techniques, are discussed considering recent clinical and preclinical developments. Despite the absence of approved disease-modifying therapies, rapid progress in biomarker development, patient stratification, and personalized approaches offers encouraging prospects for more effective interventions across the FTD spectrum. PubMed/MEDLINE was searched for peer-reviewed articles on FTD diagnosis and management; reference lists of key articles were screened to identify additional sources.
2024-03-21 | Distinctive whole-brain cell types predict tissue damage patterns in thirteen neurodegenerative conditions
For over a century, brain research narrative has mainly centered on neuron cells. Accordingly, most neurodegenerative studies focus on neuronal dysfunction and their selective vulnerability, while we lack comprehensive analyses of other major cell types’ contribution. By unifying spatial gene expression, structural MRI, and cell deconvolution, here we describe how the human brain distribution of canonical cell types extensively predicts tissue damage in 13 neurodegenerative conditions, including early- and late-onset Alzheimer’s disease, Parkinson’s disease, dementia with Lewy bodies, amyotrophic lateral sclerosis, mutations in presenilin-1, and 3 clinical variants of frontotemporal lobar degeneration (behavioral variant, semantic and non-fluent primary progressive aphasia) along with associated three-repeat and four-repeat tauopathies and TDP43 proteinopathies types A and C. We reconstructed comprehensive whole-brain reference maps of cellular abundance for six major cell types and identified characteristic axes of spatial overlapping with atrophy. Our results support the strong mediating role of non-neuronal cells, primarily microglia and astrocytes, in spatial vulnerability to tissue loss in neurodegeneration, with distinct and shared across-disorder pathomechanisms. These observations provide critical insights into the multicellular pathophysiology underlying spatiotemporal advance in neurodegeneration. Notably, they also emphasize the need to exceed the current neuro-centric view of brain diseases, supporting the imperative for cell-specific therapeutic targets in neurodegeneration.
2019-10-28 | Behavioral Variant Frontotemporal Dementia as a Serious Complication of Spontaneous Intracranial Hypotension.
Behavioral variant frontotemporal dementia (bvFTD) is a devastating early onset dementia. Symptoms of bvFTD may be caused by spontaneous intracranial hypotension (SIH), a treatable disorder, but no comprehensive study of such patients has been reported. To describe detailed characteristics of a large cohort of patients with SIH and symptoms of bvFTD. We identified patients with SIH who met clinical criteria for bvFTD. Patients were compared to a cohort of SIH patients without bvFTD. The mean age for the 21 men and 8 women was 52.9 yr (range, 37-65 yr). All 29 patients with bvFTD symptoms had hypersomnolence. Magnetic resonance imaging showed brain sagging in all patients, cerebrospinal fluid (CSF) opening pressure low in about half of patients, but a spinal CSF leak could not be detected in any patient. All patients underwent epidural blood patching, but 26 patients eventually underwent 1 or more surgical procedures. Overall, a good outcome was obtained in 21 patients (72%); 20 (91%) of 22 patients who had not undergone prior Chiari surgery compared to 1 (14%) of 7 patients who did undergo Chiari surgery (P < .003). Compared to SIH patients without symptoms of bvFTD (n = 547), those with bvFTD symptoms were older, more often male, less often demonstrated CSF leak on spinal imaging, and more often underwent surgery (P < .02). bvFTD in SIH is rare and associated with brain sagging and hypersomnolence. Spinal CSF leaks are rarely detected. bvFTD symptoms are often refractory to the usual percutaneous procedures but most patients can be cured.
2019-01-15 | Molecular Mechanisms of Neurodegeneration Related to C9orf72 Hexanucleotide Repeat Expansion.
Two clinically distinct diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), have recently been classified as two extremes of the FTD/ALS spectrum. The neuropathological correlate of FTD is frontotemporal lobar degeneration (FTLD), characterized by tau-, TDP-43-, and FUS-immunoreactive neuronal inclusions. An earlier discovery that a hexanucleotide repeat expansion mutation in chromosome 9 open reading frame 72 ( C9orf72 ) gene causes ALS and FTD established a special subtype of ALS and FTLD with TDP-43 pathology (C9FTD/ALS). Normal individuals carry 2–10 hexanucleotide GGGGCC repeats in the C9orf72 gene, while more than a few hundred repeats represent a risk for ALS and FTD. The proposed molecular mechanisms by which C9orf72 repeat expansions induce neurodegenerative changes are C9orf72 loss-of-function through haploinsufficiency, RNA toxic gain-of-function, and gain-of-function through the accumulation of toxic dipeptide repeat proteins. However, many more cellular processes are affected by pathological processes in C9FTD/ALS, including nucleocytoplasmic transport, RNA processing, normal function of nucleolus, formation of membraneless organelles, translation, ubiquitin proteasome system, Notch signalling pathway, granule transport, and normal function of TAR DNA-binding protein 43 (TDP-43). Although the exact molecular mechanisms through which C9orf72 repeat expansions account for neurodegeneration have not been elucidated, some potential therapeutics, such as antisense oligonucleotides targeting hexanucleotide GGGGCC repeats in mRNA, were successful in preclinical trials and are awaiting phase 1 clinical trials. In this review, we critically discuss each proposed mechanism and provide insight into the most recent studies aiming to elucidate the molecular underpinnings of C9FTD/ALS.
2018-04-10 | Auto-antibodies against P/Q- and N-type voltage-dependent calcium channels mimicking frontotemporal dementia
The behavioral variant of frontotemporal dementia is usually a sporadic and progressive neurodegenerative disorder. Here, we report the subacute onset of a frontotemporal dementia phenotype with a treatable etiology. The patient has a history of rheumatoid arthritis, episcleritis, and thyroid eye disease on immunosuppressive therapy. He experienced a rapid personality change, including inappropriate behavior, which suggested frontotemporal dementia. Results of imaging and neuropsychological testing also suggested frontotemporal dementia. Because of his autoimmune diseases and unusually short onset of symptoms, serum paraneoplastic panel and cerebrospinal fluid were analyzed and revealed elevated P/Q- and N-type calcium channel antibodies. Treatment with therapeutic plasma exchange resulted in a rapid improvement of his behavior and cognition. This case suggests that there may be some treatable causes of frontotemporal dementia symptomatology, that is, paraneoplastic antibodies. In the context of atypical features of frontotemporal dementia, practitioners should maintain a high index of suspicion.
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Drug Discovery Landscape
3 orphan drug designations for Behavioral variant of frontotemporal dementia.
3 orphan drug designations for Behavioral variant of frontotemporal dementia.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
2ʹ-O-(2-methoxyethyl) antisense oligonucleotide targeting microtubule-associated protein tau pre-mRNA | oligonucleotides | EMA | — | Biogen Netherlands B.V. |
Tolfenamic acid | small molecules | EMA | — | RV Developpement |
Methylthioninium | small molecules | EMA | Pharma Gateway AB |
“Terminated” – programs with discontinued clinical trials, or with no updates reported for 5 years after completion or 12 years after the last trial started.
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