RARE DISEASE
Adult-onset autosomal dominant leukodystrophy
Adult-onset autosomal dominant leukodystrophy
Adult-onset autosomal dominant leukodystrophy
Synonyms: ADLD, Adult-onset autosomal dominant demyelinating leukodystrophy
Synonyms: ADLD, Adult-onset autosomal dominant demyelinating leukodystrophy
Synonyms: ADLD, Adult-onset autosomal dominant demyelinating leukodystrophy
Drug discovery
0
drugs
With orphan designations
Overview
Adult-onset autosomal dominant leukodystrophy (ADLD) is a rare neurodegenerative disorder caused by LMNB1 gene duplications or deletions upstream of the gene, leading to lamin B1 overexpression and central nervous system demyelination. It typically manifests in the 4th–6th decade with autonomic dysfunction (e.g., neurogenic bladder, orthostatic hypotension), followed by cerebellar ataxia, pyramidal signs, and mild cognitive decline. MRI reveals confluent white matter hyperintensities, corpus callosum atrophy, and brainstem/spinal cord atrophy. Prognosis includes progressive disability over 10–20 years post-onset [1][2][14].
Burden
Progressive loss of independence due to gait instability, spasticity, and autonomic failure. Multidisciplinary care (neurology, urology, physiatry) is required, with significant socioeconomic impacts on families [1][10][14]. Early diagnosis remains challenging due to overlap with multiple sclerosis and adult-onset leukoencephalopathies [3][6].
Therapies
No disease-modifying therapies exist. Management focuses on symptomatic relief:
- Autonomic dysfunction: Midodrine for hypotension, anticholinergics for bladder urgency [14].
- Motor impairments: Physical/occupational therapy, mobility aids [12].
- Genetic counseling for autosomal dominant inheritance (50% transmission risk) [8][14].
Categories: rare developmental anomalies during embryogenesis, rare genetic diseases, rare neurological diseases, rare ophthalmic disorders
Research Papers
29 drug discovery papers about Adult-onset autosomal dominant leukodystrophy, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
29 drug discovery papers about Adult-onset autosomal dominant leukodystrophy, with 1 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
oligonucleotides
2026-09-15 | Functional validation of allele-specific LMNB1 silencing in patient-derived astrocytes as a therapeutic option for Autosomal Dominant Leukodystrophy
Abstract Adult-onset Autosomal Dominant Leukodystrophy (ADLD) is a rare fatal leukodystrophy caused by increased LMNB1 gene dosage, most commonly resulting from duplication of the LMNB1 locus. Because ADLD is a gene dosage disorder, selective reduction of pathological LMNB1 expression represents a rational therapeutic strategy. Although allele-specific RNA interference has previously been shown to lower LMNB1 levels in patient-derived fibroblasts and directly reprogrammed neurons, its therapeutic effects have not been evaluated in disease-relevant human glial cells or using functional efficacy endpoints. Here, we established human induced pluripotent stem cell-derived astrocytes from ADLD patients as a human glial model in which to validate allele-specific LMNB1 silencing across molecular, cellular, and functional readouts. ADLD astrocytes recapitulated increased LMNB1 expression and characteristic nuclear abnormalities and displayed transcriptional alterations affecting extracellular matrix organization, calcium homeostasis, metabolism and RNA processing. Functionally, these cells also exhibited functional phenotypes suitable for therapeutic evaluation: astrocyte-conditioned medium impaired the viability of both murine and human oligodendroglial cultures, while conditioned-medium and direct astrocyte-seeding paradigms revealed impaired post-lesion myelin recovery in lysolecithin-treated cerebellar organotypic slices. Allele-specific LMNB1 silencing restored physiological LMNB1 levels, corrected nuclear abnormalities, attenuated astrocyte-mediated oligodendroglial toxicity, improved post-lesion myelin recovery, and was associated with selective transcriptional programs associated with extracellular support and cholesterol metabolism. Together, these findings provide molecular, cellular, and functional validation of allele-specific LMNB1 dosage correction in patient-derived human astrocytes and offer key support for LMNB1-lowering strategies in disease-relevant human glial cells.
2026-08-11 | LMNB1 reduction is a potential therapeutic strategy in a mouse model of Autosomal Dominant Leukodystrophy.
Autosomal dominant leukodystrophy (ADLD) is a fatal-adult-onset CNS demyelinating disorder for which no treatment exists. The majority of ADLD cases are caused by duplications of the lamin B1 (LMNB1) gene, resulting in increased LMNB1 expression. While reducing LMNB1 levels represents a logical therapeutic strategy, its efficacy has not been previously demonstrated in any in vivo model. Mouse models with oligodendrocyte-specific human LMNB1 (hLMNB1) overexpression recapitulate salient features of ADLD. Using a modified version of this model, where hLMNB1 can be inducibly downregulated, we demonstrated that hLMNB1 reduction can prevent or substantially ameliorate disease progression. Therapeutic effects were maximized when hLMNB1 reduction was induced before expected symptom onset, resulting in improvements in behavioral, biochemical, histopathological, and survival measures relative to untreated animals. Reducing hLMNB1 levels after symptom onset led to improved survival, but mixed results for other disease phenotypes. In addition, we identified potential biomarkers that track disease progression. Furthermore, we demonstrated that near-complete knockdown of murine LMNB1 expression in adulthood did not result in any overt CNS phenotype. Together, these results provide a proof of concept supporting LMNB1 reduction as a therapeutic strategy and offer a rationale for treatments aimed at lowering levels of this protein in ADLD.
2023-08-07 | An oligodendrocyte silencer element underlies the pathogenic impact of lamin B1 structural variants
Abstract The role of non-coding regulatory elements and how they might contribute to tissue type specificity of disease phenotypes is poorly understood. Autosomal Dominant Leukodystrophy (ADLD) is a fatal, adult-onset, neurological disorder that is characterized by extensive CNS demyelination. Most cases of ADLD are caused by tandem genomic duplications involving the lamin B1 gene ( LMNB1 ) while a small subset are caused by genomic deletions upstream of the gene. Utilizing data from recently identified families that carry LMNB1 gene duplications but do not exhibit demyelination, ADLD patient tissues, CRISPR modified cell lines and mouse models, we have identified a novel silencer element that is lost in ADLD patients and that specifically targets overexpression to oligodendrocytes. This element consists of CTCF binding sites that mediate three-dimensional chromatin looping involving the LMNB1 and the recruitment of the PRC2 repressor complex. Loss of the silencer element in ADLD identifies a previously unknown role for silencer elements in tissue specificity and disease causation.
2020-05-18 | Allele-specific silencing as treatment for gene duplication disorders: proof-of-principle in autosomal dominant leukodystrophy.
Allele-specific silencing by RNA interference (ASP-siRNA) holds promise as a therapeutic strategy for downregulating a single mutant allele with minimal suppression of the corresponding wild-type allele. This approach has been effectively used to target autosomal dominant mutations and single nucleotide polymorphisms linked with aberrantly expanded trinucleotide repeats. Here, we propose ASP-siRNA as a preferable choice to target duplicated disease genes, avoiding potentially harmful excessive downregulation. As a proof-of-concept, we studied autosomal dominant adult-onset demyelinating leukodystrophy (ADLD) due to lamin B1 (LMNB1) duplication, a hereditary, progressive and fatal disorder affecting myelin in the CNS. Using a reporter system, we screened the most efficient ASP-siRNAs preferentially targeting one of the alleles at rs1051644 (average minor allele frequency: 0.45) located in the 3' untranslated region of the gene. We identified four siRNAs with a high efficacy and allele-specificity, which were tested in ADLD patient-derived fibroblasts. Three of the small interfering RNAs were highly selective for the target allele and restored both LMNB1 mRNA and protein levels close to control levels. Furthermore, small interfering RNA treatment abrogates the ADLD-specific phenotypes in fibroblasts and in two disease-relevant cellular models: murine oligodendrocytes overexpressing human LMNB1, and neurons directly reprogrammed from patients' fibroblasts. In conclusion, we demonstrated that ASP-silencing by RNA interference is a suitable and promising therapeutic option for ADLD. Moreover, our results have a broad translational value extending to several pathological conditions linked to gene-gain in copy number variations.
2015-08-25 | Lamin B1 overexpression increases nuclear rigidity in autosomal dominant leukodystrophy fibroblasts.
The architecture and structural mechanics of the cell nucleus are defined by the nuclear lamina, which is formed by A- and B-type lamins. Recently, gene duplication and protein overexpression of lamin B1 (LB1) have been reported in pedigrees with autosomal dominant leukodystrophy (ADLD). However, how the overexpression of LB1 affects nuclear mechanics and function and how it may result in pathology remain unexplored. Here, we report that in primary human skin fibroblasts derived from ADLD patients, LB1, but not other lamins, is overexpressed at the nuclear lamina and specifically enhances nuclear stiffness. Transient transfection of LB1 in HEK293 and neuronal N2a cells mimics the mechanical phenotype of ADLD nuclei. Notably, in ADLD fibroblasts, reducing LB1 protein levels by shRNA knockdown restores elasticity values to those indistinguishable from control fibroblasts. Moreover, isolated nuclei from ADLD fibroblasts display a reduced nuclear ion channel open probability on voltage-step application, suggesting that biophysical changes induced by LB1 overexpression may alter nuclear signaling cascades in somatic cells. Overall, the overexpression of LB1 in ADLD cells alters nuclear mechanics and is linked to changes in nuclear signaling, which could help explain the pathogenesis of this disease.
small molecules
2025-03-03 | A high throughput, high content screen for non-toxic small molecules that reduce levels of the nuclear lamina protein, Lamin B1.
Lamin B1 (LMNB1) is an intermediate filament protein that is an integral component of the nuclear lamina, a structure that is critical for nuclear organization and function. Mutations involving the lamin B1 gene cause the adult-onset demyelinating disorder, Autosomal Dominant Leukodystrophy (ADLD) which is charactered by increased lamin B1 expression. Increased LMNB1 expression is also associated with poorer outcomes in multiple cancer subtypes. Reducing LMNB1 is thus an attractive therapeutic pathway for ADLD and potentially other diseases. Here we present the results of a high throughput / high content screen (HTS/HCS) to identify small molecules that reduce LMNB1 levels. Approximately 97,000 molecules were screened using an inducible mouse fibroblast model of LMNB1 overexpression that we have previously generated. Two small molecules, Pubchem CID 662896 and CID 5308648, were identified that reduced LMNB1 in a dose dependent manner without causing cellular toxicity and corrected nuclear abnormalities associated with LMNB1 overexpression, a hallmark of ADLD. CID 662896 also reduced LMNB1 levels in ADLD patient fibroblast samples, exhibited favorable "drug-like" physicochemical properties and crossed the blood brain barrier in mouse studies. While CID 662896 may be a promising candidate for ADLD therapy, further investigations are required to determine its mechanism of action and ability to target disease relevant cell types.
2023-05-31 | Minocycline protects against microgliopathy in a Csf1r haplo-insufficient mouse model of adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP)
Abstract Background Mutations in colony-stimulating factor 1 receptor (CSF1R) are known to cause adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), which has been recently demonstrated as a primary microgliopathy characterized by cognitive impairment. Although the molecular mechanism underlying CSF1R-mediated microgliopathy remains unclear, therapeutic strategies have generally targeted modulation of microglial function. In particular, the microglial inhibitor, minocycline, has been shown to attenuate learning and memory deficits in several neurodegenerative diseases. The objectives of this study were to investigate the pathogenic mechanisms underlying ALSP and to explore the therapeutic effects of minocycline in an in vivo model of ALSP. We hypothesized that inhibiting microglial activation via minocycline could reverse the behavior and pathological defects in ALSP model mice. Methods We generated a Csf1r haploinsufficiency mouse model of ALSP using CRISPR/Cas9 genome editing and conducted electrophysiological recordings of long-term potentiation (LTP) and behavioral tests to validate the recapitulation of clinical ALSP characteristics in 8- to 11-month-old mice. RNA-sequencing was used to explore enriched gene expression in the molecular pathogenesis of ALSP. Microglial activation was assessed by immunofluorescent detection of Iba1 and CD68 in brain sections of male ALSP mice and pro-inflammatory activation and phagocytosis were assessed in Csf1r +/− microglia. Therapeutic effects were assessed by behavioral tests, histological analysis, and morphological examination after four weeks of intraperitoneal injection with minocycline or vehicle control in Csf1r +/− mice and wild-type control littermates. Results We found that synaptic function was reduced in LTP recordings of neurons in the hippocampal CA1 region, while behavioral tests showed impaired spatial and cognitive memory specifically in male Csf1r +/− mice. Increased activation, pro-inflammatory cytokine production, and enhanced phagocytic capacity were also observed in Csf1r +/− microglia. Treatment with minocycline could suppress the activation of Csf1r +/− microglia both in vitro and in vivo. Notably, the behavioral and pathological deficits in Csf1r +/− mice were partially rescued by minocycline administration, potentially due to inhibition of microglial inflammation and phagocytosis in Csf1r +/− mice. Conclusions Our study shows that CSF1R deficiency results in aberrant microglial activation, characterized by a pro-inflammatory phenotype and enhanced phagocytosis of myelin. Our results also indicate that microglial inhibition by minocycline can ameliorate behavioral impairment and ALSP pathogenesis in CSF1R-deficient male mice, suggesting a potential therapeutic target for CSF1R-related leukoencephalopathy. Collectively, these data support that minocycline confers protective effects against CSF1R-related microgliopathy in male ALSP model mice.
2022-03-31 | A high-content drug screening strategy to identify protein level modulators for genetic diseases: A proof-of-principle in autosomal dominant leukodystrophy.
In genetic diseases, the most prevalent mechanism of pathogenicity is an altered expression of dosage-sensitive genes. Drugs that restore physiological levels of these genes should be effective in treating the associated conditions. We developed a screening strategy, based on a bicistronic dual-reporter vector, for identifying compounds that modulate protein levels, and used it in a pharmacological screening approach. To provide a proof-of-principle, we chose autosomal dominant leukodystrophy (ADLD), an ultra-rare adult-onset neurodegenerative disorder caused by lamin B1 (LMNB1) overexpression. We used a stable Chinese hamster ovary (CHO) cell line that simultaneously expresses an AcGFP reporter fused to LMNB1 and a Ds-Red normalizer. Using high-content imaging analysis, we screened a library of 717 biologically active compounds and approved drugs, and identified alvespimycin, an HSP90 inhibitor, as a positive hit. We confirmed that alvespimycin can reduce LMNB1 levels by 30%-80% in five different cell lines (fibroblasts, NIH3T3, CHO, COS-7, and rat primary glial cells). In ADLD fibroblasts, alvespimycin reduced cytoplasmic LMNB1 by about 50%. We propose this approach for effectively identifying potential drugs for treating genetic diseases associated with deletions/duplications and paving the way toward Phase II clinical trials.
2021-07-19 | Development and Optimization of a High-Content Analysis Platform to Identify Suppressors of Lamin B1 Overexpression as a Therapeutic Strategy for Autosomal Dominant Leukodystrophy.
Autosomal dominant leukodystrophy (ADLD) is a fatal, progressive adult-onset disease characterized by widespread central nervous system (CNS) demyelination and significant morbidity. The late age of onset together with the relatively slow disease progression provides a large therapeutic window for the disorder. However, no treatment exists for ADLD, representing an urgent and unmet clinical need. We have previously shown that ADLD is caused by duplications of the lamin B1 gene causing increased expression of the lamin B1 protein, a major constituent of the nuclear lamina, and demonstrated that transgenic mice with oligodendrocyte-specific overexpression of lamin B1 exhibit temporal and histopathological features reminiscent of the human disease. As increased levels of lamin B1 are the causative event triggering ADLD, approaches aimed at reducing lamin B1 levels and associated functional consequences represent a promising strategy for discovery of small-molecule ADLD therapeutics. To this end, we have created an inducible cell culture model of lamin B1 overexpression and developed high-content analysis in connection with multivariate analysis to define, analyze, and quantify lamin B1 expression and its associated abnormal nuclear phenotype in mouse embryonic fibroblasts (MEFs). The assay has been optimized to meet high-throughput screening (HTS) criteria in multiday variability studies. To control for batch-to-batch variation in the primary MEFs, we have implemented a screening strategy that employs sentinel cells to avoid costly losses during HTS. We posit the assay will identify bona fide suppressors of lamin B1 pathophysiology as candidates for development into potential therapies for ADLD.
2020-10-09 | Cell signaling pathways in autosomal-dominant leukodystrophy (ADLD): the intriguing role of the astrocytes
Autosomal-dominant leukodystrophy (ADLD) is a rare fatal neurodegenerative disorder with overexpression of the nuclear lamina component, Lamin B1 due to LMNB1 gene duplication or deletions upstream of the gene. The molecular mechanisms responsible for driving the onset and development of this pathology are not clear yet. Vacuolar demyelination seems to be one of the most significant histopathological observations of ADLD. Considering the role of oligodendrocytes, astrocytes, and leukemia inhibitory factor (LIF)-activated signaling pathways in the myelination processes, this work aims to analyze the specific alterations in different cell populations from patients with LMNB1 duplications and engineered cellular models overexpressing Lamin B1 protein. Our results point out, for the first time, that astrocytes may be pivotal in the evolution of the disease. Indeed, cells from ADLD patients and astrocytes overexpressing LMNB1 show severe ultrastructural nuclear alterations, not present in oligodendrocytes overexpressing LMNB1. Moreover, the accumulation of Lamin B1 in astrocytes induces a reduction in LIF and in LIF-Receptor (LIF-R) levels with a consequential decrease in LIF secretion. Therefore, in both our cellular models, Jak/Stat3 and PI3K/Akt axes, downstream of LIF/LIF-R, are downregulated. Significantly, the administration of exogenous LIF can partially reverse the toxic effects induced by Lamin B1 accumulation with differences between astrocytes and oligodendrocytes, highlighting that LMNB1 overexpression drastically affects astrocytic function reducing their fundamental support to oligodendrocytes in the myelination process. In addition, inflammation has also been investigated, showing an increased activation in ADLD patients' cells.
cell therapies
2022-01-04 | Adult‐onset leukoencephalopathy caused by CSF1R mutations: Is all that glitters gold?
In a clinical and genetic characterization of 149 unrelated individuals with adult-onset leukoencephalopathy, Tsai et al. identified 5 patients with CSF1R-related hereditary leukodystrophy with spheroids (HLDS), including 1 with the p.Thr79Met variant located in the extracellular immunoglobulin-like domain (IgLD).1 This finding may have a major clinical impact, as so far all the HLDS-related variants were located in the intracellular tyrosine kinase domain (TyrKD).2 The p.Thr79Met variant has been considered as HLDS-causing variant because of its absence in population databases, predictions of bioinformatics program, and in vitro functional analysis, showing the loss of CSF1-induced autophosphorylation of CSF1 receptor (CSF1R) in HeLa cells transfected with the mutant CSF1R expression plasmid.1 In our opinion, this conclusion needs further evidence. Indeed, the patient was very old at disease onset, being 86 years (which would be the latest age at HLDS onset ever reported), and had multiple risk factors for leukoaraiosis, including hypertension, diabetes, hyperlipidemia, smoking, and kidney failure. Moreover, no examination such as cerebral PET and CSF analysis for investigating common causes of dementia has been reported, and no consideration about genetic variant and disease co-segregation has been given.1 Finally, in vitro functional analysis should be interpreted carefully, as the CSF1R function depends on the dimerization of two CSF1R, and in HLDS patients, a wild-type CSF1R is co-expressed with the mutant one, in contrast to in vitro experiments.3 Hence, the impact of loss-of-function (LOF) variants in vivo might be different based on their position in the TyrKD or IgLD (Fig. 1).2, 4 For instance, the p.Pro132Leu variant, located in the IgLD, has been associated with a recessive CSF1R-related syndrome named BANDDOS (brain abnormalities, neurodegeneration, and dysosteosclerosis).4 Neither the proband's mother nor the maternal grandfather, both with the p.Pro132Leu variant in heterozygous state, developed HLDS, despite in vitro functional analysis suggested a LOF by showing a decrease of ~50% in the JNK phosphorylation level activated by CSF1 treatment.4 HLDS is an autosomal dominant disease characterized by relentlessly progressive dementia, incomplete penetrance,5 and highly variable age at onset and course even in the same family.6, 7 Hematopoietic stem cell transplantation may be a therapeutic strategy,8 but its appropriate timing is difficult to define, and it is associated with mortality and morbidity which increase with increasing age.9 This framework clearly shows why the erroneous interpretation of a CSF1R variant as HLDS-causing variant is distressing for the patients and their families, and should be avoided as far as may be. The authors declare no financial or other conflicts of interest.
2020-07-06 | Allogeneic HSCT for adult-onset leukoencephalopathy with spheroids and pigmented glia.
Adult-onset leukoencephalopathy with spheroids and pigmented glia (ALSP) is an autosomal dominant leukoencephalopathy caused by mutations in colony stimulating factor 1 receptor (CSF1R). Here we report clinical and imaging outcomes following allogeneic haematopoietic stem cell transplantation (HSCT) in two patients with ALSP at the University of California, San Francisco between January 2016 and December 2017. Patient 1 proceeded to transplantation at age 53 with a haplo-identical sibling donor. Patient 2, whose sister and mother had died of the disease, proceeded to transplantation at age 49 with a 12/12 human leukocyte antigen-matched unrelated donor. Both patients received reduced intensity conditioning regimens. At 28 and 26 months post-HSCT, respectively, both patients were alive, without evidence of graft-versus-host disease, with major infection at 1 year in one and new-onset seizures in the other. In both cases, neurological worsening continued post-HSCT; however, the progression in cognitive deficits, overall functional status and gait impairment gradually stabilized. There was continued progression of parkinsonism in both patients. On brain MRI, within 1 year there was stabilization of T2/FLAIR abnormalities, and after 2 years there was complete resolution of abnormal multifocal reduced diffusion. In summary, after >2 years of follow-up, allogeneic HSCT in ALSP led to interval resolution of diffusion MRI abnormalities, stabilization of T2/FLAIR MRI abnormalities, and partial clinical stabilization, supportive of treatment response. Allogeneic HSCT may be beneficial in ALSP by providing a supply of bone marrow-derived brain-engrafting myeloid cells with donor wild-type CSF1R to repopulate the microglial niche.
gene therapies
2025-03-23 | A rare case of late adult-onset leukodystrophy due to CSF1R mutation
The debilitating autosomal dominant inherited white matter illness known as CSF1R-related disorder (CSF1R-RD) is marked by a variety of symptoms, including cognitive impairment, neuropsychiatric abnormalities, and motor symptoms such as ataxia, seizures, and pyramidal and extrapyramidal signs. Previously, CSF1R-RD was known as adult-onset leukoencephalopathy with pigmented glia and axonal spheroids. We report a case of a 31-year-old previously healthy female who presented with progressive slowness of activities, cognitive decline, behavioral changes, speech disturbances, and motor deficits over 18 months. The illness began insidiously with bradykinesia, executive dysfunction, and inappropriate emotional responses, later evolving to spasticity, aphasia, pseudobulbar affect, urinary and fecal incontinence, and dystonia of the right upper limb. Neurological examination revealed spastic dysarthria, global cognitive impairment (MoCA score: 6), spastic quadriparesis (right > left), exaggerated reflexes, and right upper limb dystonia. MRI brain showed symmetrical T2/FLAIR hyperintensities with diffusion restriction in the periventricular white matter of the frontal and parietal lobes, along with corpus callosal atrophy. Extensive metabolic, infectious, autoimmune, and demyelinating workup was unremarkable. Whole-exome sequencing identified a pathogenic mutation in the CSF1R gene, confirming the diagnosis of adult-onset leukodystrophy with CSF1R mutation (ALSP). This case highlights the diagnostic challenges in adult-onset leukodystrophies due to their heterogeneous presentations. Recognition of characteristic neuroimaging findings and early genetic testing are pivotal for accurate diagnosis, particularly in rapidly progressive neurodegenerative disorders. This case underscores the importance of considering CSF1R-related leukoencephalopathy in young adults with cognitive decline, motor dysfunction, and distinctive MRI features.
2025-03-06 | Case report: LMNB1 duplication-mediated autosomal dominant adult leukodystrophy in a Chinese family and literature review of Chinese patients.
Adult-onset autosomal dominant leukodystrophy (ADLD) is a rare, slowly progressive, and fatal neurodegenerative disorder characterized by central nervous system white matter loss due to LMNB1 gene abnormalities encoding laminB1. However, not all LMNB1 mutations lead to ADLD. Currently, two genetic alterations have been identified in association with the pathogenesis of ADLD: LMNB1 gene tandem duplication and LMNB1 gene upstream deletions. We report a case of a 60-year-old man diagnosed with ADLD, with pyramidal tract dysfunction and autonomic abnormalities as the main clinical manifestations. MRI revealed bilateral symmetric high signal intensities in the white matter of the medulla oblongata, middle cerebellar peduncles, cerebral peduncle, periventricular white matter, centrum semi vale, and the pressure region of the corpus callosum. Whole exome sequencing results indicated 73.6Kb duplicate copy number variation signals in the 5q23.2 region of the proband's chromosome. The Multiplex ligation-dependent probe amplification (MLPA) experiment results indicate recurrent mutations across all exons (exon1-11) of the LMNB1 gene. This is the eighth ADLD pedigree from China. We conducted a literature review of all ADLD pedigrees in China and summarized the characteristics of Chinese patients with ADLD to raise awareness of ADLD disease.
oligonucleotides
2026-09-15 | Functional validation of allele-specific LMNB1 silencing in patient-derived astrocytes as a therapeutic option for Autosomal Dominant Leukodystrophy
Abstract Adult-onset Autosomal Dominant Leukodystrophy (ADLD) is a rare fatal leukodystrophy caused by increased LMNB1 gene dosage, most commonly resulting from duplication of the LMNB1 locus. Because ADLD is a gene dosage disorder, selective reduction of pathological LMNB1 expression represents a rational therapeutic strategy. Although allele-specific RNA interference has previously been shown to lower LMNB1 levels in patient-derived fibroblasts and directly reprogrammed neurons, its therapeutic effects have not been evaluated in disease-relevant human glial cells or using functional efficacy endpoints. Here, we established human induced pluripotent stem cell-derived astrocytes from ADLD patients as a human glial model in which to validate allele-specific LMNB1 silencing across molecular, cellular, and functional readouts. ADLD astrocytes recapitulated increased LMNB1 expression and characteristic nuclear abnormalities and displayed transcriptional alterations affecting extracellular matrix organization, calcium homeostasis, metabolism and RNA processing. Functionally, these cells also exhibited functional phenotypes suitable for therapeutic evaluation: astrocyte-conditioned medium impaired the viability of both murine and human oligodendroglial cultures, while conditioned-medium and direct astrocyte-seeding paradigms revealed impaired post-lesion myelin recovery in lysolecithin-treated cerebellar organotypic slices. Allele-specific LMNB1 silencing restored physiological LMNB1 levels, corrected nuclear abnormalities, attenuated astrocyte-mediated oligodendroglial toxicity, improved post-lesion myelin recovery, and was associated with selective transcriptional programs associated with extracellular support and cholesterol metabolism. Together, these findings provide molecular, cellular, and functional validation of allele-specific LMNB1 dosage correction in patient-derived human astrocytes and offer key support for LMNB1-lowering strategies in disease-relevant human glial cells.
2026-08-11 | LMNB1 reduction is a potential therapeutic strategy in a mouse model of Autosomal Dominant Leukodystrophy.
Autosomal dominant leukodystrophy (ADLD) is a fatal-adult-onset CNS demyelinating disorder for which no treatment exists. The majority of ADLD cases are caused by duplications of the lamin B1 (LMNB1) gene, resulting in increased LMNB1 expression. While reducing LMNB1 levels represents a logical therapeutic strategy, its efficacy has not been previously demonstrated in any in vivo model. Mouse models with oligodendrocyte-specific human LMNB1 (hLMNB1) overexpression recapitulate salient features of ADLD. Using a modified version of this model, where hLMNB1 can be inducibly downregulated, we demonstrated that hLMNB1 reduction can prevent or substantially ameliorate disease progression. Therapeutic effects were maximized when hLMNB1 reduction was induced before expected symptom onset, resulting in improvements in behavioral, biochemical, histopathological, and survival measures relative to untreated animals. Reducing hLMNB1 levels after symptom onset led to improved survival, but mixed results for other disease phenotypes. In addition, we identified potential biomarkers that track disease progression. Furthermore, we demonstrated that near-complete knockdown of murine LMNB1 expression in adulthood did not result in any overt CNS phenotype. Together, these results provide a proof of concept supporting LMNB1 reduction as a therapeutic strategy and offer a rationale for treatments aimed at lowering levels of this protein in ADLD.
2023-08-07 | An oligodendrocyte silencer element underlies the pathogenic impact of lamin B1 structural variants
Abstract The role of non-coding regulatory elements and how they might contribute to tissue type specificity of disease phenotypes is poorly understood. Autosomal Dominant Leukodystrophy (ADLD) is a fatal, adult-onset, neurological disorder that is characterized by extensive CNS demyelination. Most cases of ADLD are caused by tandem genomic duplications involving the lamin B1 gene ( LMNB1 ) while a small subset are caused by genomic deletions upstream of the gene. Utilizing data from recently identified families that carry LMNB1 gene duplications but do not exhibit demyelination, ADLD patient tissues, CRISPR modified cell lines and mouse models, we have identified a novel silencer element that is lost in ADLD patients and that specifically targets overexpression to oligodendrocytes. This element consists of CTCF binding sites that mediate three-dimensional chromatin looping involving the LMNB1 and the recruitment of the PRC2 repressor complex. Loss of the silencer element in ADLD identifies a previously unknown role for silencer elements in tissue specificity and disease causation.
2020-05-18 | Allele-specific silencing as treatment for gene duplication disorders: proof-of-principle in autosomal dominant leukodystrophy.
Allele-specific silencing by RNA interference (ASP-siRNA) holds promise as a therapeutic strategy for downregulating a single mutant allele with minimal suppression of the corresponding wild-type allele. This approach has been effectively used to target autosomal dominant mutations and single nucleotide polymorphisms linked with aberrantly expanded trinucleotide repeats. Here, we propose ASP-siRNA as a preferable choice to target duplicated disease genes, avoiding potentially harmful excessive downregulation. As a proof-of-concept, we studied autosomal dominant adult-onset demyelinating leukodystrophy (ADLD) due to lamin B1 (LMNB1) duplication, a hereditary, progressive and fatal disorder affecting myelin in the CNS. Using a reporter system, we screened the most efficient ASP-siRNAs preferentially targeting one of the alleles at rs1051644 (average minor allele frequency: 0.45) located in the 3' untranslated region of the gene. We identified four siRNAs with a high efficacy and allele-specificity, which were tested in ADLD patient-derived fibroblasts. Three of the small interfering RNAs were highly selective for the target allele and restored both LMNB1 mRNA and protein levels close to control levels. Furthermore, small interfering RNA treatment abrogates the ADLD-specific phenotypes in fibroblasts and in two disease-relevant cellular models: murine oligodendrocytes overexpressing human LMNB1, and neurons directly reprogrammed from patients' fibroblasts. In conclusion, we demonstrated that ASP-silencing by RNA interference is a suitable and promising therapeutic option for ADLD. Moreover, our results have a broad translational value extending to several pathological conditions linked to gene-gain in copy number variations.
2015-08-25 | Lamin B1 overexpression increases nuclear rigidity in autosomal dominant leukodystrophy fibroblasts.
The architecture and structural mechanics of the cell nucleus are defined by the nuclear lamina, which is formed by A- and B-type lamins. Recently, gene duplication and protein overexpression of lamin B1 (LB1) have been reported in pedigrees with autosomal dominant leukodystrophy (ADLD). However, how the overexpression of LB1 affects nuclear mechanics and function and how it may result in pathology remain unexplored. Here, we report that in primary human skin fibroblasts derived from ADLD patients, LB1, but not other lamins, is overexpressed at the nuclear lamina and specifically enhances nuclear stiffness. Transient transfection of LB1 in HEK293 and neuronal N2a cells mimics the mechanical phenotype of ADLD nuclei. Notably, in ADLD fibroblasts, reducing LB1 protein levels by shRNA knockdown restores elasticity values to those indistinguishable from control fibroblasts. Moreover, isolated nuclei from ADLD fibroblasts display a reduced nuclear ion channel open probability on voltage-step application, suggesting that biophysical changes induced by LB1 overexpression may alter nuclear signaling cascades in somatic cells. Overall, the overexpression of LB1 in ADLD cells alters nuclear mechanics and is linked to changes in nuclear signaling, which could help explain the pathogenesis of this disease.
small molecules
2025-03-03 | A high throughput, high content screen for non-toxic small molecules that reduce levels of the nuclear lamina protein, Lamin B1.
Lamin B1 (LMNB1) is an intermediate filament protein that is an integral component of the nuclear lamina, a structure that is critical for nuclear organization and function. Mutations involving the lamin B1 gene cause the adult-onset demyelinating disorder, Autosomal Dominant Leukodystrophy (ADLD) which is charactered by increased lamin B1 expression. Increased LMNB1 expression is also associated with poorer outcomes in multiple cancer subtypes. Reducing LMNB1 is thus an attractive therapeutic pathway for ADLD and potentially other diseases. Here we present the results of a high throughput / high content screen (HTS/HCS) to identify small molecules that reduce LMNB1 levels. Approximately 97,000 molecules were screened using an inducible mouse fibroblast model of LMNB1 overexpression that we have previously generated. Two small molecules, Pubchem CID 662896 and CID 5308648, were identified that reduced LMNB1 in a dose dependent manner without causing cellular toxicity and corrected nuclear abnormalities associated with LMNB1 overexpression, a hallmark of ADLD. CID 662896 also reduced LMNB1 levels in ADLD patient fibroblast samples, exhibited favorable "drug-like" physicochemical properties and crossed the blood brain barrier in mouse studies. While CID 662896 may be a promising candidate for ADLD therapy, further investigations are required to determine its mechanism of action and ability to target disease relevant cell types.
2023-05-31 | Minocycline protects against microgliopathy in a Csf1r haplo-insufficient mouse model of adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP)
Abstract Background Mutations in colony-stimulating factor 1 receptor (CSF1R) are known to cause adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), which has been recently demonstrated as a primary microgliopathy characterized by cognitive impairment. Although the molecular mechanism underlying CSF1R-mediated microgliopathy remains unclear, therapeutic strategies have generally targeted modulation of microglial function. In particular, the microglial inhibitor, minocycline, has been shown to attenuate learning and memory deficits in several neurodegenerative diseases. The objectives of this study were to investigate the pathogenic mechanisms underlying ALSP and to explore the therapeutic effects of minocycline in an in vivo model of ALSP. We hypothesized that inhibiting microglial activation via minocycline could reverse the behavior and pathological defects in ALSP model mice. Methods We generated a Csf1r haploinsufficiency mouse model of ALSP using CRISPR/Cas9 genome editing and conducted electrophysiological recordings of long-term potentiation (LTP) and behavioral tests to validate the recapitulation of clinical ALSP characteristics in 8- to 11-month-old mice. RNA-sequencing was used to explore enriched gene expression in the molecular pathogenesis of ALSP. Microglial activation was assessed by immunofluorescent detection of Iba1 and CD68 in brain sections of male ALSP mice and pro-inflammatory activation and phagocytosis were assessed in Csf1r +/− microglia. Therapeutic effects were assessed by behavioral tests, histological analysis, and morphological examination after four weeks of intraperitoneal injection with minocycline or vehicle control in Csf1r +/− mice and wild-type control littermates. Results We found that synaptic function was reduced in LTP recordings of neurons in the hippocampal CA1 region, while behavioral tests showed impaired spatial and cognitive memory specifically in male Csf1r +/− mice. Increased activation, pro-inflammatory cytokine production, and enhanced phagocytic capacity were also observed in Csf1r +/− microglia. Treatment with minocycline could suppress the activation of Csf1r +/− microglia both in vitro and in vivo. Notably, the behavioral and pathological deficits in Csf1r +/− mice were partially rescued by minocycline administration, potentially due to inhibition of microglial inflammation and phagocytosis in Csf1r +/− mice. Conclusions Our study shows that CSF1R deficiency results in aberrant microglial activation, characterized by a pro-inflammatory phenotype and enhanced phagocytosis of myelin. Our results also indicate that microglial inhibition by minocycline can ameliorate behavioral impairment and ALSP pathogenesis in CSF1R-deficient male mice, suggesting a potential therapeutic target for CSF1R-related leukoencephalopathy. Collectively, these data support that minocycline confers protective effects against CSF1R-related microgliopathy in male ALSP model mice.
2022-03-31 | A high-content drug screening strategy to identify protein level modulators for genetic diseases: A proof-of-principle in autosomal dominant leukodystrophy.
In genetic diseases, the most prevalent mechanism of pathogenicity is an altered expression of dosage-sensitive genes. Drugs that restore physiological levels of these genes should be effective in treating the associated conditions. We developed a screening strategy, based on a bicistronic dual-reporter vector, for identifying compounds that modulate protein levels, and used it in a pharmacological screening approach. To provide a proof-of-principle, we chose autosomal dominant leukodystrophy (ADLD), an ultra-rare adult-onset neurodegenerative disorder caused by lamin B1 (LMNB1) overexpression. We used a stable Chinese hamster ovary (CHO) cell line that simultaneously expresses an AcGFP reporter fused to LMNB1 and a Ds-Red normalizer. Using high-content imaging analysis, we screened a library of 717 biologically active compounds and approved drugs, and identified alvespimycin, an HSP90 inhibitor, as a positive hit. We confirmed that alvespimycin can reduce LMNB1 levels by 30%-80% in five different cell lines (fibroblasts, NIH3T3, CHO, COS-7, and rat primary glial cells). In ADLD fibroblasts, alvespimycin reduced cytoplasmic LMNB1 by about 50%. We propose this approach for effectively identifying potential drugs for treating genetic diseases associated with deletions/duplications and paving the way toward Phase II clinical trials.
2021-07-19 | Development and Optimization of a High-Content Analysis Platform to Identify Suppressors of Lamin B1 Overexpression as a Therapeutic Strategy for Autosomal Dominant Leukodystrophy.
Autosomal dominant leukodystrophy (ADLD) is a fatal, progressive adult-onset disease characterized by widespread central nervous system (CNS) demyelination and significant morbidity. The late age of onset together with the relatively slow disease progression provides a large therapeutic window for the disorder. However, no treatment exists for ADLD, representing an urgent and unmet clinical need. We have previously shown that ADLD is caused by duplications of the lamin B1 gene causing increased expression of the lamin B1 protein, a major constituent of the nuclear lamina, and demonstrated that transgenic mice with oligodendrocyte-specific overexpression of lamin B1 exhibit temporal and histopathological features reminiscent of the human disease. As increased levels of lamin B1 are the causative event triggering ADLD, approaches aimed at reducing lamin B1 levels and associated functional consequences represent a promising strategy for discovery of small-molecule ADLD therapeutics. To this end, we have created an inducible cell culture model of lamin B1 overexpression and developed high-content analysis in connection with multivariate analysis to define, analyze, and quantify lamin B1 expression and its associated abnormal nuclear phenotype in mouse embryonic fibroblasts (MEFs). The assay has been optimized to meet high-throughput screening (HTS) criteria in multiday variability studies. To control for batch-to-batch variation in the primary MEFs, we have implemented a screening strategy that employs sentinel cells to avoid costly losses during HTS. We posit the assay will identify bona fide suppressors of lamin B1 pathophysiology as candidates for development into potential therapies for ADLD.
2020-10-09 | Cell signaling pathways in autosomal-dominant leukodystrophy (ADLD): the intriguing role of the astrocytes
Autosomal-dominant leukodystrophy (ADLD) is a rare fatal neurodegenerative disorder with overexpression of the nuclear lamina component, Lamin B1 due to LMNB1 gene duplication or deletions upstream of the gene. The molecular mechanisms responsible for driving the onset and development of this pathology are not clear yet. Vacuolar demyelination seems to be one of the most significant histopathological observations of ADLD. Considering the role of oligodendrocytes, astrocytes, and leukemia inhibitory factor (LIF)-activated signaling pathways in the myelination processes, this work aims to analyze the specific alterations in different cell populations from patients with LMNB1 duplications and engineered cellular models overexpressing Lamin B1 protein. Our results point out, for the first time, that astrocytes may be pivotal in the evolution of the disease. Indeed, cells from ADLD patients and astrocytes overexpressing LMNB1 show severe ultrastructural nuclear alterations, not present in oligodendrocytes overexpressing LMNB1. Moreover, the accumulation of Lamin B1 in astrocytes induces a reduction in LIF and in LIF-Receptor (LIF-R) levels with a consequential decrease in LIF secretion. Therefore, in both our cellular models, Jak/Stat3 and PI3K/Akt axes, downstream of LIF/LIF-R, are downregulated. Significantly, the administration of exogenous LIF can partially reverse the toxic effects induced by Lamin B1 accumulation with differences between astrocytes and oligodendrocytes, highlighting that LMNB1 overexpression drastically affects astrocytic function reducing their fundamental support to oligodendrocytes in the myelination process. In addition, inflammation has also been investigated, showing an increased activation in ADLD patients' cells.
cell therapies
2022-01-04 | Adult‐onset leukoencephalopathy caused by CSF1R mutations: Is all that glitters gold?
In a clinical and genetic characterization of 149 unrelated individuals with adult-onset leukoencephalopathy, Tsai et al. identified 5 patients with CSF1R-related hereditary leukodystrophy with spheroids (HLDS), including 1 with the p.Thr79Met variant located in the extracellular immunoglobulin-like domain (IgLD).1 This finding may have a major clinical impact, as so far all the HLDS-related variants were located in the intracellular tyrosine kinase domain (TyrKD).2 The p.Thr79Met variant has been considered as HLDS-causing variant because of its absence in population databases, predictions of bioinformatics program, and in vitro functional analysis, showing the loss of CSF1-induced autophosphorylation of CSF1 receptor (CSF1R) in HeLa cells transfected with the mutant CSF1R expression plasmid.1 In our opinion, this conclusion needs further evidence. Indeed, the patient was very old at disease onset, being 86 years (which would be the latest age at HLDS onset ever reported), and had multiple risk factors for leukoaraiosis, including hypertension, diabetes, hyperlipidemia, smoking, and kidney failure. Moreover, no examination such as cerebral PET and CSF analysis for investigating common causes of dementia has been reported, and no consideration about genetic variant and disease co-segregation has been given.1 Finally, in vitro functional analysis should be interpreted carefully, as the CSF1R function depends on the dimerization of two CSF1R, and in HLDS patients, a wild-type CSF1R is co-expressed with the mutant one, in contrast to in vitro experiments.3 Hence, the impact of loss-of-function (LOF) variants in vivo might be different based on their position in the TyrKD or IgLD (Fig. 1).2, 4 For instance, the p.Pro132Leu variant, located in the IgLD, has been associated with a recessive CSF1R-related syndrome named BANDDOS (brain abnormalities, neurodegeneration, and dysosteosclerosis).4 Neither the proband's mother nor the maternal grandfather, both with the p.Pro132Leu variant in heterozygous state, developed HLDS, despite in vitro functional analysis suggested a LOF by showing a decrease of ~50% in the JNK phosphorylation level activated by CSF1 treatment.4 HLDS is an autosomal dominant disease characterized by relentlessly progressive dementia, incomplete penetrance,5 and highly variable age at onset and course even in the same family.6, 7 Hematopoietic stem cell transplantation may be a therapeutic strategy,8 but its appropriate timing is difficult to define, and it is associated with mortality and morbidity which increase with increasing age.9 This framework clearly shows why the erroneous interpretation of a CSF1R variant as HLDS-causing variant is distressing for the patients and their families, and should be avoided as far as may be. The authors declare no financial or other conflicts of interest.
2020-07-06 | Allogeneic HSCT for adult-onset leukoencephalopathy with spheroids and pigmented glia.
Adult-onset leukoencephalopathy with spheroids and pigmented glia (ALSP) is an autosomal dominant leukoencephalopathy caused by mutations in colony stimulating factor 1 receptor (CSF1R). Here we report clinical and imaging outcomes following allogeneic haematopoietic stem cell transplantation (HSCT) in two patients with ALSP at the University of California, San Francisco between January 2016 and December 2017. Patient 1 proceeded to transplantation at age 53 with a haplo-identical sibling donor. Patient 2, whose sister and mother had died of the disease, proceeded to transplantation at age 49 with a 12/12 human leukocyte antigen-matched unrelated donor. Both patients received reduced intensity conditioning regimens. At 28 and 26 months post-HSCT, respectively, both patients were alive, without evidence of graft-versus-host disease, with major infection at 1 year in one and new-onset seizures in the other. In both cases, neurological worsening continued post-HSCT; however, the progression in cognitive deficits, overall functional status and gait impairment gradually stabilized. There was continued progression of parkinsonism in both patients. On brain MRI, within 1 year there was stabilization of T2/FLAIR abnormalities, and after 2 years there was complete resolution of abnormal multifocal reduced diffusion. In summary, after >2 years of follow-up, allogeneic HSCT in ALSP led to interval resolution of diffusion MRI abnormalities, stabilization of T2/FLAIR MRI abnormalities, and partial clinical stabilization, supportive of treatment response. Allogeneic HSCT may be beneficial in ALSP by providing a supply of bone marrow-derived brain-engrafting myeloid cells with donor wild-type CSF1R to repopulate the microglial niche.
gene therapies
2025-03-23 | A rare case of late adult-onset leukodystrophy due to CSF1R mutation
The debilitating autosomal dominant inherited white matter illness known as CSF1R-related disorder (CSF1R-RD) is marked by a variety of symptoms, including cognitive impairment, neuropsychiatric abnormalities, and motor symptoms such as ataxia, seizures, and pyramidal and extrapyramidal signs. Previously, CSF1R-RD was known as adult-onset leukoencephalopathy with pigmented glia and axonal spheroids. We report a case of a 31-year-old previously healthy female who presented with progressive slowness of activities, cognitive decline, behavioral changes, speech disturbances, and motor deficits over 18 months. The illness began insidiously with bradykinesia, executive dysfunction, and inappropriate emotional responses, later evolving to spasticity, aphasia, pseudobulbar affect, urinary and fecal incontinence, and dystonia of the right upper limb. Neurological examination revealed spastic dysarthria, global cognitive impairment (MoCA score: 6), spastic quadriparesis (right > left), exaggerated reflexes, and right upper limb dystonia. MRI brain showed symmetrical T2/FLAIR hyperintensities with diffusion restriction in the periventricular white matter of the frontal and parietal lobes, along with corpus callosal atrophy. Extensive metabolic, infectious, autoimmune, and demyelinating workup was unremarkable. Whole-exome sequencing identified a pathogenic mutation in the CSF1R gene, confirming the diagnosis of adult-onset leukodystrophy with CSF1R mutation (ALSP). This case highlights the diagnostic challenges in adult-onset leukodystrophies due to their heterogeneous presentations. Recognition of characteristic neuroimaging findings and early genetic testing are pivotal for accurate diagnosis, particularly in rapidly progressive neurodegenerative disorders. This case underscores the importance of considering CSF1R-related leukoencephalopathy in young adults with cognitive decline, motor dysfunction, and distinctive MRI features.
2025-03-06 | Case report: LMNB1 duplication-mediated autosomal dominant adult leukodystrophy in a Chinese family and literature review of Chinese patients.
Adult-onset autosomal dominant leukodystrophy (ADLD) is a rare, slowly progressive, and fatal neurodegenerative disorder characterized by central nervous system white matter loss due to LMNB1 gene abnormalities encoding laminB1. However, not all LMNB1 mutations lead to ADLD. Currently, two genetic alterations have been identified in association with the pathogenesis of ADLD: LMNB1 gene tandem duplication and LMNB1 gene upstream deletions. We report a case of a 60-year-old man diagnosed with ADLD, with pyramidal tract dysfunction and autonomic abnormalities as the main clinical manifestations. MRI revealed bilateral symmetric high signal intensities in the white matter of the medulla oblongata, middle cerebellar peduncles, cerebral peduncle, periventricular white matter, centrum semi vale, and the pressure region of the corpus callosum. Whole exome sequencing results indicated 73.6Kb duplicate copy number variation signals in the 5q23.2 region of the proband's chromosome. The Multiplex ligation-dependent probe amplification (MLPA) experiment results indicate recurrent mutations across all exons (exon1-11) of the LMNB1 gene. This is the eighth ADLD pedigree from China. We conducted a literature review of all ADLD pedigrees in China and summarized the characteristics of Chinese patients with ADLD to raise awareness of ADLD disease.
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