RARE DISEASE
Sanfilippo syndrome type A
Sanfilippo syndrome type A
Sanfilippo syndrome type A
Synonyms: Heparan sulfamidase deficiency, MPS3A, MPSIIIA, Mucopolysaccharidosis type 3A, Mucopolysaccharidosis type IIIA
Synonyms: Heparan sulfamidase deficiency, MPS3A, MPSIIIA, Mucopolysaccharidosis type 3A, Mucopolysaccharidosis type IIIA
Synonyms: Heparan sulfamidase deficiency, MPS3A, MPSIIIA, Mucopolysaccharidosis type 3A, Mucopolysaccharidosis type IIIA
Drug discovery
22
drugs
With orphan designations
Overview
Sanfilippo syndrome type A (MPS IIIA) is a rare, fatal autosomal recessive lysosomal storage disorder caused by SGSH gene mutations, leading to sulfamidase deficiency and heparan sulfate accumulation. Initial symptoms (speech/developmental delays, hyperactivity, sleep disturbances) emerge in early childhood, followed by severe neurodegeneration, cognitive decline, and premature death (average lifespan 15–18 years) [1][6][12]. No curative treatments exist, though gene therapy trials show early promise [1][18].
Therapies
Investigational gene therapies (e.g., UX111/ABO-102, AAV9 vector) aim to restore sulfamidase activity, demonstrating reduced heparan sulfate levels and neurocognitive stabilization in early-phase trials [1][16][18].
Supportive care includes seizure management, physical/behavioral therapies, and palliative interventions [2][6][13].
Categories: rare bone diseases, rare developmental anomalies during embryogenesis, rare genetic diseases, rare inborn errors of metabolism, rare neurological diseases, rare ophthalmic disorders, rare transplant-related disorders
Research Papers
271 drug discovery papers about Sanfilippo syndrome type A, with 4 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
271 drug discovery papers about Sanfilippo syndrome type A, with 4 first-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
cell therapies
2025-11-19 | Allogeneic hematopoietic stem cell transplantation modulates neurodevelopmental trajectories in mucopolysaccharidosis: a longitudinal study of subtype-specific outcomes and age-dependent efficacy.
Mucopolysaccharidosis (MPS) involves neurodevelopmental decline due to lysosomal dysfunction. Hematopoietic stem cell transplantation (HSCT) may modify disease progression, but subtype-specific outcomes remain unclear. Fifty-seven MPS patients (aged 1-8 years) undergoing HSCT in Shanghai (2019-2024) were assessed longitudinally using Griffiths Mental Development Scales-Chinese (GDS-C) pre-HSCT and at 3, 12, and 24 months post-HSCT. Linear mixed models evaluated timepoint, age, and subtype effects. HSCT significantly improved locomotor function (F = 111.57, p < 0.001), with greatest gains in MPS III (β = 59.57) and age-dependent decline (β = - 2.46/year). Personal-social function improved modestly (F = 4.44, p = 0.039), while language/eye-hand coordination showed progressive gains (p ≤ 0.001). Subtype influenced language (F = 3.75) and coordination (F = 2.89), with attenuated responses in MPS II. No Timepoint × Subtype interactions suggested uniform temporal effects. HSCT stabilizes/improves neurodevelopment in MPS, modulated by subtype and transplant age. Early intervention optimizes outcomes, particularly for MPS III. Culturally adapted GDS-C enables precise monitoring, guiding HSCT timing and rehabilitation.
2025-10-18 | The Neuroimmune Landscape of the Lysosomal Storage Disorder Sanfilippo Syndrome.
Lysosomal storage disorders (LSDs) such as Sanfilippo syndrome (Mucopolysaccharidosis type III) are characterized by impaired lysosomal degradation due to inherited in lysosomal proteins. This dysfunction leads to the accumulation of undegraded substrates, such as heparan sulfate, ultimately leading to progressive neuroinflammation and neurodegeneration. Despite well-defined genetic causes, no disease-modifying therapies exist for Sanfilippo syndrome. While microglia, the brain's resident immune cells, can play both protective and pathogenic roles, the contribution of neuroinflammation to LSD pathology remains underexplored. This review examines the contribution of neuroinflammation to Sanfilippo syndrome, emphasizing emerging mechanisms involving TLR4 signaling, inflammasome activation, the cGAS-STING pathway, and lysosomal biogenesis regulators such as TFE family transcription factors. We also discuss the potential of cellular therapies to modulate neuroimmune responses and offer new therapeutic avenues. By integrating insights from neuroimmunology and lysosomal biology, we aim to identify shared mechanisms and therapeutic targets across Sanfilippo syndrome and related LSDs.
2025-03-19 | Allogeneic hematopoietic stem cell transplantation for mucopolysaccharidosis patients: a single-center experience and assessment of quality of life.
Allogeneic hematopoietic stem cell transplantation (HSCT) has proven to be a viable treatment option for patients with mucopolysaccharidoses (MPS). We investigate the efficacy and improvements in the quality of life of HSCT in pediatric patients with MPS. A retrospective analysis of transplantation data from 46 cases of MPS from a single institution in China was conducted. The cohort of 46 patients included 9 cases of MPS I, 16 cases of MPS II, 15 cases of MPS IVA and 6 cases of MPS VI. The median age at diagnosis was 2.59 years. The median age at transplantation was 3.80 years. The median follow-up time was 3.1 years (range, 0.8-8.1 years) and 43 patients were alive. The incidence of grades II to IV aGVHD was 17.4%, wherein the incidence of grades III and IV aGVHD was 4.3%. The incidence of moderate-to-severe cGVHD was 6.5%. GAGs urinary excretion decreased and enzyme activity levels reached normal. After HSCT, multiple bone dysplasia, upper-airway obstruction and recurrent otitis media were significantly improved; vision, corneal clouding, cardiovascular disease, hepatosplenomegaly and hydrocephalus were improved or remained stable; neurological symptoms were improved or remained stable in most patients but progressed in others; the patients with MPS IH/S and MPS II reached nearly normal growth rate of height and weight. Meanwhile, the patients with MPS IH, MPS IVA and MPS VI remained poor growth after HSCT. The Activities of Daily Living (ADL) scores were improved in most patients with MPS. ADL scores in patients with severe phenotypes were lower than health control subjects and patients with attenuated phenotypes. HSCT is a good therapeutic option for MPS and improves the quality of life of patients. MPS patients with attenuated phenotypes provide a better outcome in ADL after HSCT.
2024-07-27 | Generation of a novel immunodeficient mouse model of Mucopolysaccharidosis type IIIA to test human stem cell-based therapies.
Mucopolysaccharidosis Type IIIA (MPSIIIA) is a rare inherited lysosomal storage disease caused by mutations in the SGSH gene. This genetic variation results in the deficiency of the N-sulfoglucosamine sulfohydrolase enzyme, preventing the breakdown of heparan sulfate within lysosomes. The progressive accumulation of partially degraded substrate ultimately leads to brain pathology, for which there is currently no approved treatment. An established MPSIIIA mouse model has proved to be a vital asset to test several brain-targeting strategies. Nonetheless, the assessment of human stem cell-based products, an emerging research field, necessitates the use of an immunocompromised xenogeneic disease model. In the present study, we addressed this issue by generating a highly immunodeficient mouse model of MPSIIIA (NOD/SCID/GammaC chain null-MPSIIIA) through five generations of crossing an established MPSIIIA mouse model and a NOD/SCID/GammaC chain null (NSG) mouse. The immune system composition, behavioural phenotype and histopathological hallmarks of the NSG-MPSIIIA model were then evaluated. We demonstrated that NSG-MPSIIIA mice display compromised adaptive immunity, ultimately facilitating the successful engraftment of human iPSC-derived neural progenitor cells in the brain up to three months post-delivery. Furthermore, female NSG-MPSIIIA exhibit spatial working memory deficits and hyperactive behaviour, similar to MPSIIIA mice, which usually manifest around 5 months of age. NSG-MPSIIIA mice also developed primary disease-related neuropathological features in common with the MPSIIIA model, including lysosomal enlargement with storage of excess sulphated heparan sulphate and increased gliosis in several areas of the brain. In the future, the NSG-MPSIIIA mouse model holds the potential to serve as a valuable platform for evaluating human stem-cell based therapies for MPSIIIA patients.
2021-07-28 | Haematopoietic stem cell gene therapy with IL-1Ra rescues cognitive loss in mucopolysaccharidosis IIIA.
Mucopolysaccharidosis IIIA is a neuronopathic lysosomal storage disease, characterised by heparan sulphate and other substrates accumulating in the brain. Patients develop behavioural disturbances and cognitive decline, a possible consequence of neuroinflammation and abnormal substrate accumulation. Interleukin (IL)-1β and interleukin-1 receptor antagonist (IL-1Ra) expression were significantly increased in both murine models and human MPSIII patients. We identified pathogenic mechanisms of inflammasome activation, including that disease-specific 2-O-sulphated heparan sulphate was essential for priming an IL-1β response via the Toll-like receptor 4 complex. However, mucopolysaccharidosis IIIA primary and secondary storage substrates, such as amyloid beta, were both required to activate the NLRP3 inflammasome and initiate IL-1β secretion. IL-1 blockade in mucopolysaccharidosis IIIA mice using IL-1 receptor type 1 knockout or haematopoietic stem cell gene therapy over-expressing IL-1Ra reduced gliosis and completely prevented behavioural phenotypes. In conclusion, we demonstrate that IL-1 drives neuroinflammation, behavioural abnormality and cognitive decline in mucopolysaccharidosis IIIA, highlighting haematopoietic stem cell gene therapy treatment with IL-1Ra as a potential neuronopathic lysosomal disease treatment.
small molecules
2026-09-21 | Drug screen and machine learning predict neuroprotective agents in a preclinical human model of childhood dementia.
Childhood dementias are a group of paediatric neurodegenerative disorders characterised by neurocognitive decline, and in many cases underpinned by pathophysiological mechanisms similar to adult-onset dementias. In this study, we use patient-derived induced pluripotent stem cells (iPSCs) from children with one of the most prevalent childhood dementias, Mucopolysaccharidosis Type IIIA (MPS IIIA), also known as Sanfilippo syndrome. The derived cortical cultures exhibit lysosomal dysfunction, heparan sulfate accumulation, progressive neurodegeneration and astrocytic reactivity, recapitulating prototypical in-vivo phenotypes. Using a multimodal drug screening platform that integrates machine learning, high-content confocal imaging, single-nuclei transcriptomics and electrophysiology, we identify at least nine repurposed compounds that significantly mitigate these adverse effects within two weeks of treatment in vitro, demonstrating potential for rapid clinical translation. This human preclinical model for MPS IIIA, coupled with a robust multimodal therapeutic interrogation platform, serves as an exemplar for advancing drug discovery for childhood dementias and the broader neurodegenerative disease spectrum.
2026-04-29 | Short-Term Oral Spermidine Supplementation Modifies Aspects of Neurodegenerative Disease in Flies and Mice With MPS III.
Mucopolysaccharidosis type III (MPS III) is a group of autosomal recessive neurodegenerative lysosomal storage disorders that causes progressive cognitive and physical impairment, predominantly in child/early adulthood. The median age of death is 17 years as there is no safe, effective treatment approved. Using faithful Drosophila and murine models of MPS III, we have characterised the MPS IIIA and MPS IIIC fly metabolome, explored the ability of oral spermidine supplementation to ameliorate clinical disease in the fly models and explored its mechanism of action in MPS IIIA mice. Spermidine is a polyamine naturally synthesised by the body. Its manufacture decreases with age. Supplementation has been reported to stimulate autophagy, reduce cell senescence and increase health/lifespan. The metabolomic evaluation confirmed that whole MPS IIIA and MPS IIIC flies exhibit a progressively deranged metabolome. Significantly up-regulated metabolites were those involved in nucleotide and purine metabolism. The most significantly down-regulated metabolites were those involved in ascorbate and aldarate metabolism. Further, spermidine levels decreased significantly in all fly genotypes with age. In short-term studies, food enriched with 5 mM spermidine improved overall fly activity and climbing ability. A 4-week study in pre-symptomatic MPS IIIA mice (3- or 6-mM spermidine, supplemented in drinking water) revealed no improvement in microgliosis or lysosomal compartment size; however, we observed a significant reduction in the astroglial response in the brain, which is believed to drive disease progression. Longer-term confirmatory studies in larger cohorts of MPS III animals are now warranted to determine whether spermidine supplementation is of benefit in preventing or slowing clinical disease in this and other childhood dementias.
2026-04-08 | Modelling synaptic dysfunction in childhood dementia using human iPSC-derived cortical networks.
Alterations in synaptic homeostasis are linked to cognitive and behavioural impairments in brain disorders. However, synaptic dysfunction in childhood dementia is poorly understood. Here, we generate human cortical circuits from induced pluripotent stem cells (iPSCs) derived from donors with Mucopolysaccharidosis Type IIIA (MPS IIIA), also known as Sanfilippo syndrome, a common form of childhood-onset dementia. Action potential firing capacity and morphology of MPS IIIA patient neurons in culture are similar to those of neurons from neurotypical donors. However, long-term neural maturation reveals excitation/inhibition imbalances caused by hyperactive excitatory synapses, disrupted network dynamics, and dysregulated gene expression linked to synaptic homeostasis. This study validates in vitro human neural models to detect neurophysiological phenotypes in childhood dementias and supports drug discovery strategies that target synaptic dysfunction to improve cognition in MPS IIIA and related brain disorders.
2025-10-01 | A case report on the treatment of autoimmune hemolytic anemia after CBT by daratumumab in a mucopolysaccharidosis type III patient.
Mucopolysaccharidosis type III, also referred to as Sanfilippo disease, is a rare hereditary lysosomal storage illness and one of the more common variants. The illness can affect all tissues and organs of the body, with the central nervous system being the most profoundly impacted. Autoimmune hemolytic anemia (AIHA) is a rare, diverse, antibody-mediated disorder characterized by the production of antibodies that target and destroy red blood cells, leading to their rapid destruction. AIHA is a prevalent and notable complication in recipients following umbilical cord blood stem cell transplantation. Immunosuppressive treatments, including intravenous immunoglobulin and rituximab, have been the primary therapeutic modalities. There is no consensus on the appropriate treatment for post-transplant severe AIHA. This article details a 5-year-old male diagnosed with mucopolysaccharidosis type III. He developed AIHA + 144 days after umbilical cord blood stem cell transplantation. Genetic testing, cranial CT, blood cell analysis, direct/indirect antihuman globulin test. Treatment encompasses red blood cell transfusion to rectify anemia, intravenous administration of methylprednisolone, calcium gluconate, alkaline solutions, plasma exchange, rituximab, gamma globulin, and more symptomatic therapies. The symptoms of hemolysis were inadequately managed throughout the disease progression and were alleviated upon therapy with daratumumab. The treatment was conducted without adverse effects, and the problem was well managed. A telephonic follow-up with the patient was conducted by our department 546 days post-discharge. The child's cognitive ability, linguistic skills, and other neurological processes remained stable without further decline. This report discusses a child with MPS III, a rare disorder characterized by complex and varied phenotypes, including distinctive facial features, short stature, cognitive regression, varying degrees of skeletal deformities, and hepatosplenomegaly. The patient has autoimmune hemolysis after umbilical cord blood transplantation. For patients who do not respond to rituximab and gamma globulin, daratumumab may be considered.
2025-08-25 | Progressive activation of the astrocyte A1 phenotype underlies microglia-astroglia crosstalk and contributes to neuroinflammation in neuronopathic MPS.
Neuroinflammation underlies neurodegenerative processes in neuronopathic mucopolysaccharidoses (MPS), with innate immunity known to have a dominating role. Here, by studying mouse models of neuronopathic MPS, we found that the neurotoxic reactive astrocytes A1 are present in the brain of MPS mice and progressively increase with age. Such A1 phenotype is associated to activated microglia and to microglia-mediated release of a subset of specific cytokines involved in the A1 phenotype. Additionally, in the mouse model of MPS-IIIA, one of the most severe neuronopathic MPS in humans, we also found that neuroinflammation proceeded concomitantly with the activation of transglutaminase 2, a multifunctional enzyme involved in a variety of cellular processes, mostly in the microglia. Moreover, amyloid deposition appears to be associated to the maintenance of these processes, indeed, inhibiting amyloid deposition in MPS-IIIA mice reduced TG2 expression, microglia activation and the relative amount of astrocyte A1 phenotype. Our results shed light on the microglia-astroglia crosstalk in neuronopathic MPS and on its implication in neuroinflammation and neurodegeneration in MPS, thus also suggesting new therapeutic targets for these diseases.
antibodies
2025-11-12 | Neuroinflammation as a Novel Therapeutic Frontier for Sanfilippo Syndrome
Glycosaminoglycans (GAGs), also named ‘mucopolysaccharides’, are nodal constituents of the connective tissue matrix which go through synthesis, demolition, and reconstruction within several cellular structures: an abnormal GAG catabolism is the basis of progressive intra-lysosomal accumulation of non-metabolized GAGs, defining all mucopolysaccharidoses (MPS), protean disorders characterized by physical abnormalities and multi-organ failure depending on the specific site of non-renewable GAGs stored. A severe cognitive decline is typically observed in the Sanfilippo syndrome, which corresponds to MPS type III, a group of four inherited neurodegenerative diseases resulting from the lack of specific enzymes involved in heparan sulfate (HS) metabolism. As a consequence, the storage of partially degraded HS fragments within lysosomes of the central nervous system elicits chain inflammatory reactions involving the NLRP3-inflammasome in microglia and astrocytes, which cease their homeostatic and immune functions and finally compromise neuron survival. This article provides an overview of the neuroinflammatory picture observed in children with MPS type III, postulating a role of HS accumulation to prime innate immunity responses which culminate with pro-inflammatory cytokine release in the brain and highlighting the relevance of interleukin-1 as a main contributor to neuroinflammation.
2017-12-18 | Reduction in Brain Heparan Sulfate with Systemic Administration of an IgG Trojan Horse–Sulfamidase Fusion Protein in the Mucopolysaccharidosis Type IIIA Mouse
Mucopolysaccharidosis Type IIIA (MPSIIIA), also known as Sanfilippo A syndrome, is an inherited neurodegenerative disease caused by mutations in the lysosomal enzyme, N-sulfoglucosamine sulfohydrolase (SGSH), also known as sulfamidase. Mutations in the SGSH enzyme, the only mammalian heparan N-sulfatase, cause accumulation of lysosomal inclusion bodies in brain cells comprising heparan sulfate (HS) glycosaminoglycans (GAGs). Treatment of MPSIIIA with intravenous recombinant SGSH is not possible because this large molecule does not cross the blood-brain barrier (BBB). BBB penetration by SGSH was enabled in the present study by re-engineering this enzyme as an IgG-SGSH fusion protein, where the IgG domain is a chimeric monoclonal antibody (mAb) against the mouse transferrin receptor (TfR), designated the cTfRMAb. The IgG domain of the fusion protein acts as a molecular Trojan horse to deliver the enzyme into brain via transport on the endogenous BBB TfR. The cTfRMAb-SGSH fusion protein bound to the mouse TfR with high affinity, ED50 = 0.74 ± 0.07 nM, and retained high SGSH enzyme activity, 10 043 ± 1003 units/mg protein, which is comparable to recombinant human SGSH. Male and female MPSIIIA mice, null for the SGSH enzyme, were treated for 6 weeks with thrice-weekly intraperitoneal injections of vehicle, 5 mg/kg of the cTfRMAb alone, or 5 mg/kg of the cTfRMAb-SGSH fusion protein, starting at the age of 2 weeks, and were euthanized 1 week after the last injection. Brain and liver HS, as determined by liquid chromatography-mass spectrometry, were elevated 30-fold and 36-fold, respectively, in the MPSIIIA mouse. Treatment of the mice with the cTfRMAb-SGSH fusion protein caused a 70% and 85% reduction in brain and liver HS, respectively. The reduction in brain HS was associated with a 28% increase in latency on the rotarod test of motor activity in male mice. The mice exhibited no injection related reactions, and only a low titer end of study antidrug antibody response was observed. In conclusion, substantial reductions in brain pathologic GAGs in a murine model of MPSIIIA are produced by chronic systemic administration of an IgG-SGSH fusion protein engineered to penetrate the BBB via receptor-mediated transport.
2014-06-20 | Insulin Receptor Antibody–Sulfamidase Fusion Protein Penetrates the Primate Blood–Brain Barrier and Reduces Glycosoaminoglycans in Sanfilippo Type A Cells
Mutations in the lysosomal enzyme, N-sulfoglucosamine sulfohydrolase (SGSH), also called sulfamidase, cause accumulation of lysosomal inclusion bodies in the brain of children born with mucopolysaccharidosis type IIIA, also called Sanfilippo type A syndrome. Enzyme replacement therapy with recombinant SGSH does not treat the brain because the enzyme is a large molecule drug that does not cross the blood-brain barrier (BBB). A BBB-penetrating form of SGSH was produced by re-engineering the enzyme as an IgG fusion protein, where the IgG domain is a monoclonal antibody (mAb) against the human insulin receptor (HIR). The HIRMAb domain of the HIRMAb-SGSH fusion protein acts as a molecular Trojan horse to ferry the fused enzyme across the BBB. The HIRMAb-SGSH was produced in stably transfected host cells and purified to homogeneity by protein A chromatography. The fusion protein reacted with antibodies against either human IgG or SGSH on Western blotting. High affinity binding to the HIR was retained following SGSH fusion to the HIRMAb, with an EC50 of 0.33 ± 0.05 nM in an HIR binding ELISA. The SGSH enzyme activity of the HIRMAb-SGSH fusion protein was 4712 ± 388 units/mg protein based on a two-step fluorometric enzyme assay. The HIRMAb-SGSH was taken up by lysosomes in MPSIIIA fibroblasts, and treatment of these cells with the fusion protein caused an 83% reduction in sulfate incorporation into lysosomal glycosoaminoglycans. The HIRMAb-SGSH fusion protein was radiolabeled with the [(125)I]-Bolton-Hunter reagent and injected intravenously in the Rhesus monkey. The brain uptake of the fusion protein was high, ∼1% injected dose/brain. Calculations, based on this level of brain uptake, suggest normalization of brain SGSH enzyme activity is possible following administration of therapeutic doses of the fusion protein. These studies describe a novel IgG-SGSH fusion protein that is a new noninvasive treatment of the brain in MPS type IIIA.
2008-06-12 | Re-Engineering Biopharmaceuticals for Delivery to Brain with Molecular Trojan Horses
Biopharmaceuticals, including recombinant proteins, monoclonal antibody therapeutics, and antisense or RNA interference drugs, cannot be developed as drugs for the brain, because these large molecules do not cross the blood-brain barrier (BBB). Biopharmaceuticals must be re-engineered to cross the BBB, and this is possible with genetically engineered molecular Trojan horses. A molecular Trojan horse is an endogenous peptide, or peptidomimetic monoclonal antibody (mAb), which enters brain from blood via receptor-mediated transport on endogenous BBB transporters. Recombinant neurotrophins, single chain Fv antibodies, or therapeutic enzymes may be re-engineered as IgG fusion proteins. The engineering of IgG-avidin fusion proteins enables the BBB delivery of biotinylated drugs. The IgG fusion proteins are new chemical entities that are dual or triple function molecules that bind multiple receptors. The fusion proteins are able both to enter the brain, by binding an endogenous BBB receptor, and to induce the desired pharmacologic effect in brain, by binding target receptors in the brain behind the BBB. The development of molecular Trojan horses for BBB drug delivery allows the re-engineering of biopharmaceuticals that, owing to the BBB problem, could not otherwise be developed as new drugs for the human brain.
proteins
2026-01-01 | Recurrent infections and immunodeficiency in a patientwith Sanfilippo syndrome (MPS type 3)
Sanfilippo syndrome (mucopolysaccharidosis type III, MPS III) is a rare lysosomal storage disorder characterized by progressive neurodegeneration, behavioral abnormalities, and multisystemic involvement, with autosomal recessive inheritance.Recent findings suggest that immune system disorders may play a role in the pathogenesis and clinical complications of the disease, in addition to the classic neurological presentation.In this case, total IgG and subclass deficiencies were detected in an 18-year-old female patient who was being monitored for frequent respiratory tract infections, and intravenous immunoglobulin (IVIG) treatment was initiated with a diagnosis of humoral immunodeficiency.A significant decrease in the incidence of post-treatment infections and hospital admissions has been observed.Immune system involvement in MPS patients may increase the risk of infection.Therefore, immunological evaluation and appropriate treatment approaches are critical for improving quality of life.
2024-11-05 | Extracellular vesicles from microglial cells activated by abnormal heparan sulfate oligosaccharides from Sanfilippo patients impair neuronal dendritic arborization.
In mucopolysaccharidosis type III (MPS III, also known as Sanfilippo syndrome), a pediatric neurodegenerative disorder, accumulation of abnormal glycosaminoglycans (GAGs) induces severe neuroinflammation by triggering the microglial pro-inflammatory cytokines production via a TLR4-dependent pathway. But the extent of the microglia contribution to the MPS III neuropathology remains unclear. Extracellular vesicles (EVs) mediate intercellular communication and are known to participate in the pathogenesis of adult neurodegenerative diseases. However, characterization of the molecular profiles of EVs released by MPS III microglia and their effects on neuronal functions have not been described. Here, we isolated EVs secreted by the microglial cells after treatment with GAGs purified from urines of Sanfilippo patients (sfGAGs-EVs) or from age-matched healthy subjects (nGAGs-EVs) to explore the EVs' proteins and small RNA profiles using LC-MS/MS and RNA sequencing. We next performed a functional assay by immunofluorescence following nGAGs- or sfGAGs-EVs uptake by WT primary cortical neurons and analyzed their extensions metrics after staining of βIII-tubulin and MAP2 by confocal microscopy. Functional enrichment analysis for both proteomics and RNA sequencing data from sfGAGs-EVs revealed a specific content involved in neuroinflammation and neurodevelopment pathways. Treatment of cortical neurons with sfGAGs-EVs induced a disease-associated phenotype demonstrated by a lower total neurite surface area, an impaired somatodendritic compartment, and a higher number of immature dendritic spines. This study shows, for the first time, that GAGs from patients with Sanfilippo syndrome can induce microglial secretion of EVs that deliver a specific molecular message to recipient naive neurons, while promoting the neuroinflammation, and depriving neurons of neurodevelopmental factors. This work provides a framework for further studies of biomarkers to evaluate efficiency of emerging therapies.
2021-04-21 | Sanfilippo Syndrome: Molecular Basis, Disease Models and Therapeutic Approaches.
Sanfilippo syndrome or mucopolysaccharidosis III is a lysosomal storage disorder caused by mutations in genes responsible for the degradation of heparan sulfate, a glycosaminoglycan located in the extracellular membrane. Undegraded heparan sulfate molecules accumulate within lysosomes leading to cellular dysfunction and pathology in several organs, with severe central nervous system degeneration as the main phenotypical feature. The exact molecular and cellular mechanisms by which impaired degradation and storage lead to cellular dysfunction and neuronal degeneration are still not fully understood. Here, we compile the knowledge on this issue and review all available animal and cellular models that can be used to contribute to increase our understanding of Sanfilippo syndrome disease mechanisms. Moreover, we provide an update in advances regarding the different and most successful therapeutic approaches that are currently under study to treat Sanfilippo syndrome patients and discuss the potential of new tools such as induced pluripotent stem cells to be used for disease modeling and therapy development.
2018-06-14 | Intrathecal/Intracerebroventricular enzyme replacement therapy for the mucopolysaccharidoses: efficacy, safety, and prospects
Introduction: The mucopolysaccharidoses (MPS) are lysosomal storage diseases (LSDs) caused by the deficiency of an enzyme involved in the breakdown of glycosaminoglycans (GAGs), which leads to GAG storage and results in multisystemic manifestations. In some of the 11 MPS types, patients could have cognitive involvement and/or secondary neurologic manifestations. Intravenous enzyme replacement therapy (ERT), already approved for several MPS types, is not able to cross the blood–brain barrier and does not address the neurologic manifestations present in most MPS types. Intrathecal (IT) or intracerebroventricular (ICV) administration of the enzyme directly into the cerebrospinal fluid (CSF) has been proposed and experienced in clinical trials and in single cases.Areas covered: This paper briefly summarizes the development of ERT to treat LSDs, particularly MPS, the technical aspects related to its CSF administration, the experience obtained so far with the IT and ICV use in several MPS types and provides an expert opinion on this subject.Expert opinion: Treatment of neuropathic MPS remains a challenge. The results of ongoing trials may bring IT and ICV administration of ERT to clinical use in the coming years, making it a therapeutic option for the treatment of neuronopathic patients in several MPS types.
other
2026-03-31 | RNA-seq dataset of brain tissue from MPSIIIA (Sgsh D31N) mouse model following antisense oligonucleotide treatment
This dataset contains RNA sequencing (RNA-seq) data generated from brain tissue of a murine model of mucopolysaccharidosis type IIIA (MPSIIIA). The model used was B6.Cg-Sgsh^MPSIIIA/PstJ mice (Jackson Laboratories), which harbor a missense mutation in the murine Sgsh gene (c.91G>A, p.D31N). Homozygous mice exhibit approximately 3–4% of normal SGSH enzymatic activity, resulting in extensive lysosomal accumulation of heparan sulfate (HS) and progressive neurodegeneration. RNA was extracted from brain tissue of wild-type, disease-model (Sgsh homozygous), and antisense oligonucleotide (ASO)-treated mice. RNA-seq libraries were prepared using the MARS-seq protocol and sequenced on an Illumina NovaSeq platform, generating single-end reads (~26 million reads per sample). Raw sequencing data are provided as FASTQ files, along with accompanying sample metadata. This dataset enables analysis of differential gene expression and transcriptional signatures associated with MPSIIIA pathology, as well as transcriptional changes following ASO-mediated reduction of EXT1 expression. The dataset is associated with the study:“Antisense oligonucleotides mediated substrate reduction therapy ameliorates heparan sulfate accumulation in MPSIIIA models. All animal procedures were approved by the Sheba Medical Center IACUC.
2024-03-27 | Cellular Organelle-Related Transcriptomic Profile Abnormalities in Neuronopathic Types of Mucopolysaccharidosis: A Comparison with Other Neurodegenerative Diseases.
Mucopolysaccharidoses (MPS) are a group of diseases caused by mutations in genes encoding lysosomal enzymes that catalyze reactions of glycosaminoglycan (GAG) degradation. As a result, GAGs accumulate in lysosomes, impairing the proper functioning of entire cells and tissues. There are 14 types/subtypes of MPS, which are differentiated by the kind(s) of accumulated GAG(s) and the type of a non-functional lysosomal enzyme. Some of these types (severe forms of MPS types I and II, MPS III, and MPS VII) are characterized by extensive central nervous system disorders. The aim of this work was to identify, using transcriptomic methods, organelle-related genes whose expression levels are changed in neuronopathic types of MPS compared to healthy cells while remaining unchanged in non-neuronopathic types of MPS. The study was conducted with fibroblast lines derived from patients with neuronopathic and non-neuronopathic types of MPS and control (healthy) fibroblasts. Transcriptomic analysis has identified genes related to cellular organelles whose expression is altered. Then, using fluorescence and electron microscopy, we assessed the morphology of selected structures. Our analyses indicated that the genes whose expression is affected in neuronopathic MPS are often associated with the structures or functions of the cell nucleus, endoplasmic reticulum, or Golgi apparatus. Electron microscopic studies confirmed disruptions in the structures of these organelles. Special attention was paid to up-regulated genes, such as PDIA3 and MFGE8, and down-regulated genes, such as ARL6IP6, ABHD5, PDE4DIP, YIPF5, and CLDN11. Of particular interest is also the GM130 (GOLGA2) gene, which encodes golgin A2, which revealed an increased expression in neuronopathic MPS types. We propose to consider the levels of mRNAs of these genes as candidates for biomarkers of neurodegeneration in MPS. These genes may also become potential targets for therapies under development for neurological disorders associated with MPS and candidates for markers of the effectiveness of these therapies. Although fibroblasts rather than nerve cells were used in this study, it is worth noting that potential genetic markers characteristic solely of neurons would be impractical in testing patients, contrary to somatic cells that can be relatively easily obtained from assessed persons.
2023-09-11 | Identification of genetic variants associated with a wide spectrum of phenotypes clinically diagnosed as Sanfilippo and Morquio syndromes using whole genome sequencing
Mucopolysaccharidoses (MPSs) are inherited lysosomal storage disorders (LSDs). MPSs are caused by excessive accumulation of mucopolysaccharides due to missing or deficiency of enzymes required for the degradation of specific macromolecules. MPS I-IV, MPS VI, MPS VII, and MPS IX are sub-types of mucopolysaccharidoses. Among these, MPS III (also known as Sanfilippo) and MPS IV (Morquio) syndromes are lethal and prevalent sub-types. This study aimed to identify causal genetic variants in cases of MPS III and MPS IV and characterize genotype-phenotype relations in Pakistan. We performed clinical, biochemical and genetic analysis using Whole Genome Sequencing (WGS) in 14 Pakistani families affected with MPS III or MPS IV. Patients were classified into MPS III by history of aggressive behaviors, dementia, clear cornea and into MPS IV by short trunk, short stature, reversed ratio of upper segment to lower segment with a short upper segment. Data analysis and variant selections were made based on segregation analysis, examination of known MPS III and MPS IV genes, gene function, gene expression, the pathogenicity of variants based on ACMG guidelines and in silico analysis. In total, 58 individuals from 14 families were included in the present study. Six families were clinically diagnosed with MPS III and eight families with MPS IV. WGS revealed variants in MPS-associated genes including NAGLU, SGSH, GALNS, GNPTG as well as the genes VWA3B , BTD , and GNPTG which have not previously associated with MPS. One family had causal variants in both GALNS and BTD . Accurate and early diagnosis of MPS in children represents a helpful step for designing therapeutic strategies to protect different organs from permanent damage. In addition, pre-natal screening and identification of genetic etiology will facilitate genetic counselling of the affected families. Identification of novel causal MPS genes might help identifying new targeted therapies to treat LSDs.
2020-05-13 | Evading the AAV Immune Response in Mucopolysaccharidoses
The humoral immune response elicited by adeno-associated virus (AAV)-mediated gene therapy for the treatment of mucopolysaccharidoses (MPS) poses a significant challenge to achieving therapeutic levels of transgene expression. Antibodies targeting the AAV capsid as well as the transgene product diminish the production of glycosaminoglycan (GAG)-degrading enzymes essential for the treatment of MPS. Patients who have antibodies against AAV capsid increase in number with age, serotype, and racial background and are excluded from the clinical trials at present. In addition, patients who have undergone AAV gene therapy are often excluded from the additional AAV gene therapy with the same serotype, since their acquired immune response (antibody) against AAV will limit further efficacy of treatment. Several methods are being developed to overcome this immune response, such as novel serotype design, antibody reduction by plasmapheresis and immunosuppression, and antibody evasion using empty capsids and enveloped AAV vectors. In this review, we examine the mechanisms of the anti-AAV humoral immune response and evaluate the strengths and weaknesses of current evasion strategies in order to provide an evidence-based recommendation on evading the immune response for future AAV-mediated gene therapies for MPS.
cell therapies
2025-11-19 | Allogeneic hematopoietic stem cell transplantation modulates neurodevelopmental trajectories in mucopolysaccharidosis: a longitudinal study of subtype-specific outcomes and age-dependent efficacy.
Mucopolysaccharidosis (MPS) involves neurodevelopmental decline due to lysosomal dysfunction. Hematopoietic stem cell transplantation (HSCT) may modify disease progression, but subtype-specific outcomes remain unclear. Fifty-seven MPS patients (aged 1-8 years) undergoing HSCT in Shanghai (2019-2024) were assessed longitudinally using Griffiths Mental Development Scales-Chinese (GDS-C) pre-HSCT and at 3, 12, and 24 months post-HSCT. Linear mixed models evaluated timepoint, age, and subtype effects. HSCT significantly improved locomotor function (F = 111.57, p < 0.001), with greatest gains in MPS III (β = 59.57) and age-dependent decline (β = - 2.46/year). Personal-social function improved modestly (F = 4.44, p = 0.039), while language/eye-hand coordination showed progressive gains (p ≤ 0.001). Subtype influenced language (F = 3.75) and coordination (F = 2.89), with attenuated responses in MPS II. No Timepoint × Subtype interactions suggested uniform temporal effects. HSCT stabilizes/improves neurodevelopment in MPS, modulated by subtype and transplant age. Early intervention optimizes outcomes, particularly for MPS III. Culturally adapted GDS-C enables precise monitoring, guiding HSCT timing and rehabilitation.
2025-10-18 | The Neuroimmune Landscape of the Lysosomal Storage Disorder Sanfilippo Syndrome.
Lysosomal storage disorders (LSDs) such as Sanfilippo syndrome (Mucopolysaccharidosis type III) are characterized by impaired lysosomal degradation due to inherited in lysosomal proteins. This dysfunction leads to the accumulation of undegraded substrates, such as heparan sulfate, ultimately leading to progressive neuroinflammation and neurodegeneration. Despite well-defined genetic causes, no disease-modifying therapies exist for Sanfilippo syndrome. While microglia, the brain's resident immune cells, can play both protective and pathogenic roles, the contribution of neuroinflammation to LSD pathology remains underexplored. This review examines the contribution of neuroinflammation to Sanfilippo syndrome, emphasizing emerging mechanisms involving TLR4 signaling, inflammasome activation, the cGAS-STING pathway, and lysosomal biogenesis regulators such as TFE family transcription factors. We also discuss the potential of cellular therapies to modulate neuroimmune responses and offer new therapeutic avenues. By integrating insights from neuroimmunology and lysosomal biology, we aim to identify shared mechanisms and therapeutic targets across Sanfilippo syndrome and related LSDs.
2025-03-19 | Allogeneic hematopoietic stem cell transplantation for mucopolysaccharidosis patients: a single-center experience and assessment of quality of life.
Allogeneic hematopoietic stem cell transplantation (HSCT) has proven to be a viable treatment option for patients with mucopolysaccharidoses (MPS). We investigate the efficacy and improvements in the quality of life of HSCT in pediatric patients with MPS. A retrospective analysis of transplantation data from 46 cases of MPS from a single institution in China was conducted. The cohort of 46 patients included 9 cases of MPS I, 16 cases of MPS II, 15 cases of MPS IVA and 6 cases of MPS VI. The median age at diagnosis was 2.59 years. The median age at transplantation was 3.80 years. The median follow-up time was 3.1 years (range, 0.8-8.1 years) and 43 patients were alive. The incidence of grades II to IV aGVHD was 17.4%, wherein the incidence of grades III and IV aGVHD was 4.3%. The incidence of moderate-to-severe cGVHD was 6.5%. GAGs urinary excretion decreased and enzyme activity levels reached normal. After HSCT, multiple bone dysplasia, upper-airway obstruction and recurrent otitis media were significantly improved; vision, corneal clouding, cardiovascular disease, hepatosplenomegaly and hydrocephalus were improved or remained stable; neurological symptoms were improved or remained stable in most patients but progressed in others; the patients with MPS IH/S and MPS II reached nearly normal growth rate of height and weight. Meanwhile, the patients with MPS IH, MPS IVA and MPS VI remained poor growth after HSCT. The Activities of Daily Living (ADL) scores were improved in most patients with MPS. ADL scores in patients with severe phenotypes were lower than health control subjects and patients with attenuated phenotypes. HSCT is a good therapeutic option for MPS and improves the quality of life of patients. MPS patients with attenuated phenotypes provide a better outcome in ADL after HSCT.
2024-07-27 | Generation of a novel immunodeficient mouse model of Mucopolysaccharidosis type IIIA to test human stem cell-based therapies.
Mucopolysaccharidosis Type IIIA (MPSIIIA) is a rare inherited lysosomal storage disease caused by mutations in the SGSH gene. This genetic variation results in the deficiency of the N-sulfoglucosamine sulfohydrolase enzyme, preventing the breakdown of heparan sulfate within lysosomes. The progressive accumulation of partially degraded substrate ultimately leads to brain pathology, for which there is currently no approved treatment. An established MPSIIIA mouse model has proved to be a vital asset to test several brain-targeting strategies. Nonetheless, the assessment of human stem cell-based products, an emerging research field, necessitates the use of an immunocompromised xenogeneic disease model. In the present study, we addressed this issue by generating a highly immunodeficient mouse model of MPSIIIA (NOD/SCID/GammaC chain null-MPSIIIA) through five generations of crossing an established MPSIIIA mouse model and a NOD/SCID/GammaC chain null (NSG) mouse. The immune system composition, behavioural phenotype and histopathological hallmarks of the NSG-MPSIIIA model were then evaluated. We demonstrated that NSG-MPSIIIA mice display compromised adaptive immunity, ultimately facilitating the successful engraftment of human iPSC-derived neural progenitor cells in the brain up to three months post-delivery. Furthermore, female NSG-MPSIIIA exhibit spatial working memory deficits and hyperactive behaviour, similar to MPSIIIA mice, which usually manifest around 5 months of age. NSG-MPSIIIA mice also developed primary disease-related neuropathological features in common with the MPSIIIA model, including lysosomal enlargement with storage of excess sulphated heparan sulphate and increased gliosis in several areas of the brain. In the future, the NSG-MPSIIIA mouse model holds the potential to serve as a valuable platform for evaluating human stem-cell based therapies for MPSIIIA patients.
2021-07-28 | Haematopoietic stem cell gene therapy with IL-1Ra rescues cognitive loss in mucopolysaccharidosis IIIA.
Mucopolysaccharidosis IIIA is a neuronopathic lysosomal storage disease, characterised by heparan sulphate and other substrates accumulating in the brain. Patients develop behavioural disturbances and cognitive decline, a possible consequence of neuroinflammation and abnormal substrate accumulation. Interleukin (IL)-1β and interleukin-1 receptor antagonist (IL-1Ra) expression were significantly increased in both murine models and human MPSIII patients. We identified pathogenic mechanisms of inflammasome activation, including that disease-specific 2-O-sulphated heparan sulphate was essential for priming an IL-1β response via the Toll-like receptor 4 complex. However, mucopolysaccharidosis IIIA primary and secondary storage substrates, such as amyloid beta, were both required to activate the NLRP3 inflammasome and initiate IL-1β secretion. IL-1 blockade in mucopolysaccharidosis IIIA mice using IL-1 receptor type 1 knockout or haematopoietic stem cell gene therapy over-expressing IL-1Ra reduced gliosis and completely prevented behavioural phenotypes. In conclusion, we demonstrate that IL-1 drives neuroinflammation, behavioural abnormality and cognitive decline in mucopolysaccharidosis IIIA, highlighting haematopoietic stem cell gene therapy treatment with IL-1Ra as a potential neuronopathic lysosomal disease treatment.
small molecules
2026-09-21 | Drug screen and machine learning predict neuroprotective agents in a preclinical human model of childhood dementia.
Childhood dementias are a group of paediatric neurodegenerative disorders characterised by neurocognitive decline, and in many cases underpinned by pathophysiological mechanisms similar to adult-onset dementias. In this study, we use patient-derived induced pluripotent stem cells (iPSCs) from children with one of the most prevalent childhood dementias, Mucopolysaccharidosis Type IIIA (MPS IIIA), also known as Sanfilippo syndrome. The derived cortical cultures exhibit lysosomal dysfunction, heparan sulfate accumulation, progressive neurodegeneration and astrocytic reactivity, recapitulating prototypical in-vivo phenotypes. Using a multimodal drug screening platform that integrates machine learning, high-content confocal imaging, single-nuclei transcriptomics and electrophysiology, we identify at least nine repurposed compounds that significantly mitigate these adverse effects within two weeks of treatment in vitro, demonstrating potential for rapid clinical translation. This human preclinical model for MPS IIIA, coupled with a robust multimodal therapeutic interrogation platform, serves as an exemplar for advancing drug discovery for childhood dementias and the broader neurodegenerative disease spectrum.
2026-04-29 | Short-Term Oral Spermidine Supplementation Modifies Aspects of Neurodegenerative Disease in Flies and Mice With MPS III.
Mucopolysaccharidosis type III (MPS III) is a group of autosomal recessive neurodegenerative lysosomal storage disorders that causes progressive cognitive and physical impairment, predominantly in child/early adulthood. The median age of death is 17 years as there is no safe, effective treatment approved. Using faithful Drosophila and murine models of MPS III, we have characterised the MPS IIIA and MPS IIIC fly metabolome, explored the ability of oral spermidine supplementation to ameliorate clinical disease in the fly models and explored its mechanism of action in MPS IIIA mice. Spermidine is a polyamine naturally synthesised by the body. Its manufacture decreases with age. Supplementation has been reported to stimulate autophagy, reduce cell senescence and increase health/lifespan. The metabolomic evaluation confirmed that whole MPS IIIA and MPS IIIC flies exhibit a progressively deranged metabolome. Significantly up-regulated metabolites were those involved in nucleotide and purine metabolism. The most significantly down-regulated metabolites were those involved in ascorbate and aldarate metabolism. Further, spermidine levels decreased significantly in all fly genotypes with age. In short-term studies, food enriched with 5 mM spermidine improved overall fly activity and climbing ability. A 4-week study in pre-symptomatic MPS IIIA mice (3- or 6-mM spermidine, supplemented in drinking water) revealed no improvement in microgliosis or lysosomal compartment size; however, we observed a significant reduction in the astroglial response in the brain, which is believed to drive disease progression. Longer-term confirmatory studies in larger cohorts of MPS III animals are now warranted to determine whether spermidine supplementation is of benefit in preventing or slowing clinical disease in this and other childhood dementias.
2026-04-08 | Modelling synaptic dysfunction in childhood dementia using human iPSC-derived cortical networks.
Alterations in synaptic homeostasis are linked to cognitive and behavioural impairments in brain disorders. However, synaptic dysfunction in childhood dementia is poorly understood. Here, we generate human cortical circuits from induced pluripotent stem cells (iPSCs) derived from donors with Mucopolysaccharidosis Type IIIA (MPS IIIA), also known as Sanfilippo syndrome, a common form of childhood-onset dementia. Action potential firing capacity and morphology of MPS IIIA patient neurons in culture are similar to those of neurons from neurotypical donors. However, long-term neural maturation reveals excitation/inhibition imbalances caused by hyperactive excitatory synapses, disrupted network dynamics, and dysregulated gene expression linked to synaptic homeostasis. This study validates in vitro human neural models to detect neurophysiological phenotypes in childhood dementias and supports drug discovery strategies that target synaptic dysfunction to improve cognition in MPS IIIA and related brain disorders.
2025-10-01 | A case report on the treatment of autoimmune hemolytic anemia after CBT by daratumumab in a mucopolysaccharidosis type III patient.
Mucopolysaccharidosis type III, also referred to as Sanfilippo disease, is a rare hereditary lysosomal storage illness and one of the more common variants. The illness can affect all tissues and organs of the body, with the central nervous system being the most profoundly impacted. Autoimmune hemolytic anemia (AIHA) is a rare, diverse, antibody-mediated disorder characterized by the production of antibodies that target and destroy red blood cells, leading to their rapid destruction. AIHA is a prevalent and notable complication in recipients following umbilical cord blood stem cell transplantation. Immunosuppressive treatments, including intravenous immunoglobulin and rituximab, have been the primary therapeutic modalities. There is no consensus on the appropriate treatment for post-transplant severe AIHA. This article details a 5-year-old male diagnosed with mucopolysaccharidosis type III. He developed AIHA + 144 days after umbilical cord blood stem cell transplantation. Genetic testing, cranial CT, blood cell analysis, direct/indirect antihuman globulin test. Treatment encompasses red blood cell transfusion to rectify anemia, intravenous administration of methylprednisolone, calcium gluconate, alkaline solutions, plasma exchange, rituximab, gamma globulin, and more symptomatic therapies. The symptoms of hemolysis were inadequately managed throughout the disease progression and were alleviated upon therapy with daratumumab. The treatment was conducted without adverse effects, and the problem was well managed. A telephonic follow-up with the patient was conducted by our department 546 days post-discharge. The child's cognitive ability, linguistic skills, and other neurological processes remained stable without further decline. This report discusses a child with MPS III, a rare disorder characterized by complex and varied phenotypes, including distinctive facial features, short stature, cognitive regression, varying degrees of skeletal deformities, and hepatosplenomegaly. The patient has autoimmune hemolysis after umbilical cord blood transplantation. For patients who do not respond to rituximab and gamma globulin, daratumumab may be considered.
2025-08-25 | Progressive activation of the astrocyte A1 phenotype underlies microglia-astroglia crosstalk and contributes to neuroinflammation in neuronopathic MPS.
Neuroinflammation underlies neurodegenerative processes in neuronopathic mucopolysaccharidoses (MPS), with innate immunity known to have a dominating role. Here, by studying mouse models of neuronopathic MPS, we found that the neurotoxic reactive astrocytes A1 are present in the brain of MPS mice and progressively increase with age. Such A1 phenotype is associated to activated microglia and to microglia-mediated release of a subset of specific cytokines involved in the A1 phenotype. Additionally, in the mouse model of MPS-IIIA, one of the most severe neuronopathic MPS in humans, we also found that neuroinflammation proceeded concomitantly with the activation of transglutaminase 2, a multifunctional enzyme involved in a variety of cellular processes, mostly in the microglia. Moreover, amyloid deposition appears to be associated to the maintenance of these processes, indeed, inhibiting amyloid deposition in MPS-IIIA mice reduced TG2 expression, microglia activation and the relative amount of astrocyte A1 phenotype. Our results shed light on the microglia-astroglia crosstalk in neuronopathic MPS and on its implication in neuroinflammation and neurodegeneration in MPS, thus also suggesting new therapeutic targets for these diseases.
antibodies
2025-11-12 | Neuroinflammation as a Novel Therapeutic Frontier for Sanfilippo Syndrome
Glycosaminoglycans (GAGs), also named ‘mucopolysaccharides’, are nodal constituents of the connective tissue matrix which go through synthesis, demolition, and reconstruction within several cellular structures: an abnormal GAG catabolism is the basis of progressive intra-lysosomal accumulation of non-metabolized GAGs, defining all mucopolysaccharidoses (MPS), protean disorders characterized by physical abnormalities and multi-organ failure depending on the specific site of non-renewable GAGs stored. A severe cognitive decline is typically observed in the Sanfilippo syndrome, which corresponds to MPS type III, a group of four inherited neurodegenerative diseases resulting from the lack of specific enzymes involved in heparan sulfate (HS) metabolism. As a consequence, the storage of partially degraded HS fragments within lysosomes of the central nervous system elicits chain inflammatory reactions involving the NLRP3-inflammasome in microglia and astrocytes, which cease their homeostatic and immune functions and finally compromise neuron survival. This article provides an overview of the neuroinflammatory picture observed in children with MPS type III, postulating a role of HS accumulation to prime innate immunity responses which culminate with pro-inflammatory cytokine release in the brain and highlighting the relevance of interleukin-1 as a main contributor to neuroinflammation.
2017-12-18 | Reduction in Brain Heparan Sulfate with Systemic Administration of an IgG Trojan Horse–Sulfamidase Fusion Protein in the Mucopolysaccharidosis Type IIIA Mouse
Mucopolysaccharidosis Type IIIA (MPSIIIA), also known as Sanfilippo A syndrome, is an inherited neurodegenerative disease caused by mutations in the lysosomal enzyme, N-sulfoglucosamine sulfohydrolase (SGSH), also known as sulfamidase. Mutations in the SGSH enzyme, the only mammalian heparan N-sulfatase, cause accumulation of lysosomal inclusion bodies in brain cells comprising heparan sulfate (HS) glycosaminoglycans (GAGs). Treatment of MPSIIIA with intravenous recombinant SGSH is not possible because this large molecule does not cross the blood-brain barrier (BBB). BBB penetration by SGSH was enabled in the present study by re-engineering this enzyme as an IgG-SGSH fusion protein, where the IgG domain is a chimeric monoclonal antibody (mAb) against the mouse transferrin receptor (TfR), designated the cTfRMAb. The IgG domain of the fusion protein acts as a molecular Trojan horse to deliver the enzyme into brain via transport on the endogenous BBB TfR. The cTfRMAb-SGSH fusion protein bound to the mouse TfR with high affinity, ED50 = 0.74 ± 0.07 nM, and retained high SGSH enzyme activity, 10 043 ± 1003 units/mg protein, which is comparable to recombinant human SGSH. Male and female MPSIIIA mice, null for the SGSH enzyme, were treated for 6 weeks with thrice-weekly intraperitoneal injections of vehicle, 5 mg/kg of the cTfRMAb alone, or 5 mg/kg of the cTfRMAb-SGSH fusion protein, starting at the age of 2 weeks, and were euthanized 1 week after the last injection. Brain and liver HS, as determined by liquid chromatography-mass spectrometry, were elevated 30-fold and 36-fold, respectively, in the MPSIIIA mouse. Treatment of the mice with the cTfRMAb-SGSH fusion protein caused a 70% and 85% reduction in brain and liver HS, respectively. The reduction in brain HS was associated with a 28% increase in latency on the rotarod test of motor activity in male mice. The mice exhibited no injection related reactions, and only a low titer end of study antidrug antibody response was observed. In conclusion, substantial reductions in brain pathologic GAGs in a murine model of MPSIIIA are produced by chronic systemic administration of an IgG-SGSH fusion protein engineered to penetrate the BBB via receptor-mediated transport.
2014-06-20 | Insulin Receptor Antibody–Sulfamidase Fusion Protein Penetrates the Primate Blood–Brain Barrier and Reduces Glycosoaminoglycans in Sanfilippo Type A Cells
Mutations in the lysosomal enzyme, N-sulfoglucosamine sulfohydrolase (SGSH), also called sulfamidase, cause accumulation of lysosomal inclusion bodies in the brain of children born with mucopolysaccharidosis type IIIA, also called Sanfilippo type A syndrome. Enzyme replacement therapy with recombinant SGSH does not treat the brain because the enzyme is a large molecule drug that does not cross the blood-brain barrier (BBB). A BBB-penetrating form of SGSH was produced by re-engineering the enzyme as an IgG fusion protein, where the IgG domain is a monoclonal antibody (mAb) against the human insulin receptor (HIR). The HIRMAb domain of the HIRMAb-SGSH fusion protein acts as a molecular Trojan horse to ferry the fused enzyme across the BBB. The HIRMAb-SGSH was produced in stably transfected host cells and purified to homogeneity by protein A chromatography. The fusion protein reacted with antibodies against either human IgG or SGSH on Western blotting. High affinity binding to the HIR was retained following SGSH fusion to the HIRMAb, with an EC50 of 0.33 ± 0.05 nM in an HIR binding ELISA. The SGSH enzyme activity of the HIRMAb-SGSH fusion protein was 4712 ± 388 units/mg protein based on a two-step fluorometric enzyme assay. The HIRMAb-SGSH was taken up by lysosomes in MPSIIIA fibroblasts, and treatment of these cells with the fusion protein caused an 83% reduction in sulfate incorporation into lysosomal glycosoaminoglycans. The HIRMAb-SGSH fusion protein was radiolabeled with the [(125)I]-Bolton-Hunter reagent and injected intravenously in the Rhesus monkey. The brain uptake of the fusion protein was high, ∼1% injected dose/brain. Calculations, based on this level of brain uptake, suggest normalization of brain SGSH enzyme activity is possible following administration of therapeutic doses of the fusion protein. These studies describe a novel IgG-SGSH fusion protein that is a new noninvasive treatment of the brain in MPS type IIIA.
2008-06-12 | Re-Engineering Biopharmaceuticals for Delivery to Brain with Molecular Trojan Horses
Biopharmaceuticals, including recombinant proteins, monoclonal antibody therapeutics, and antisense or RNA interference drugs, cannot be developed as drugs for the brain, because these large molecules do not cross the blood-brain barrier (BBB). Biopharmaceuticals must be re-engineered to cross the BBB, and this is possible with genetically engineered molecular Trojan horses. A molecular Trojan horse is an endogenous peptide, or peptidomimetic monoclonal antibody (mAb), which enters brain from blood via receptor-mediated transport on endogenous BBB transporters. Recombinant neurotrophins, single chain Fv antibodies, or therapeutic enzymes may be re-engineered as IgG fusion proteins. The engineering of IgG-avidin fusion proteins enables the BBB delivery of biotinylated drugs. The IgG fusion proteins are new chemical entities that are dual or triple function molecules that bind multiple receptors. The fusion proteins are able both to enter the brain, by binding an endogenous BBB receptor, and to induce the desired pharmacologic effect in brain, by binding target receptors in the brain behind the BBB. The development of molecular Trojan horses for BBB drug delivery allows the re-engineering of biopharmaceuticals that, owing to the BBB problem, could not otherwise be developed as new drugs for the human brain.
proteins
2026-01-01 | Recurrent infections and immunodeficiency in a patientwith Sanfilippo syndrome (MPS type 3)
Sanfilippo syndrome (mucopolysaccharidosis type III, MPS III) is a rare lysosomal storage disorder characterized by progressive neurodegeneration, behavioral abnormalities, and multisystemic involvement, with autosomal recessive inheritance.Recent findings suggest that immune system disorders may play a role in the pathogenesis and clinical complications of the disease, in addition to the classic neurological presentation.In this case, total IgG and subclass deficiencies were detected in an 18-year-old female patient who was being monitored for frequent respiratory tract infections, and intravenous immunoglobulin (IVIG) treatment was initiated with a diagnosis of humoral immunodeficiency.A significant decrease in the incidence of post-treatment infections and hospital admissions has been observed.Immune system involvement in MPS patients may increase the risk of infection.Therefore, immunological evaluation and appropriate treatment approaches are critical for improving quality of life.
2024-11-05 | Extracellular vesicles from microglial cells activated by abnormal heparan sulfate oligosaccharides from Sanfilippo patients impair neuronal dendritic arborization.
In mucopolysaccharidosis type III (MPS III, also known as Sanfilippo syndrome), a pediatric neurodegenerative disorder, accumulation of abnormal glycosaminoglycans (GAGs) induces severe neuroinflammation by triggering the microglial pro-inflammatory cytokines production via a TLR4-dependent pathway. But the extent of the microglia contribution to the MPS III neuropathology remains unclear. Extracellular vesicles (EVs) mediate intercellular communication and are known to participate in the pathogenesis of adult neurodegenerative diseases. However, characterization of the molecular profiles of EVs released by MPS III microglia and their effects on neuronal functions have not been described. Here, we isolated EVs secreted by the microglial cells after treatment with GAGs purified from urines of Sanfilippo patients (sfGAGs-EVs) or from age-matched healthy subjects (nGAGs-EVs) to explore the EVs' proteins and small RNA profiles using LC-MS/MS and RNA sequencing. We next performed a functional assay by immunofluorescence following nGAGs- or sfGAGs-EVs uptake by WT primary cortical neurons and analyzed their extensions metrics after staining of βIII-tubulin and MAP2 by confocal microscopy. Functional enrichment analysis for both proteomics and RNA sequencing data from sfGAGs-EVs revealed a specific content involved in neuroinflammation and neurodevelopment pathways. Treatment of cortical neurons with sfGAGs-EVs induced a disease-associated phenotype demonstrated by a lower total neurite surface area, an impaired somatodendritic compartment, and a higher number of immature dendritic spines. This study shows, for the first time, that GAGs from patients with Sanfilippo syndrome can induce microglial secretion of EVs that deliver a specific molecular message to recipient naive neurons, while promoting the neuroinflammation, and depriving neurons of neurodevelopmental factors. This work provides a framework for further studies of biomarkers to evaluate efficiency of emerging therapies.
2021-04-21 | Sanfilippo Syndrome: Molecular Basis, Disease Models and Therapeutic Approaches.
Sanfilippo syndrome or mucopolysaccharidosis III is a lysosomal storage disorder caused by mutations in genes responsible for the degradation of heparan sulfate, a glycosaminoglycan located in the extracellular membrane. Undegraded heparan sulfate molecules accumulate within lysosomes leading to cellular dysfunction and pathology in several organs, with severe central nervous system degeneration as the main phenotypical feature. The exact molecular and cellular mechanisms by which impaired degradation and storage lead to cellular dysfunction and neuronal degeneration are still not fully understood. Here, we compile the knowledge on this issue and review all available animal and cellular models that can be used to contribute to increase our understanding of Sanfilippo syndrome disease mechanisms. Moreover, we provide an update in advances regarding the different and most successful therapeutic approaches that are currently under study to treat Sanfilippo syndrome patients and discuss the potential of new tools such as induced pluripotent stem cells to be used for disease modeling and therapy development.
2018-06-14 | Intrathecal/Intracerebroventricular enzyme replacement therapy for the mucopolysaccharidoses: efficacy, safety, and prospects
Introduction: The mucopolysaccharidoses (MPS) are lysosomal storage diseases (LSDs) caused by the deficiency of an enzyme involved in the breakdown of glycosaminoglycans (GAGs), which leads to GAG storage and results in multisystemic manifestations. In some of the 11 MPS types, patients could have cognitive involvement and/or secondary neurologic manifestations. Intravenous enzyme replacement therapy (ERT), already approved for several MPS types, is not able to cross the blood–brain barrier and does not address the neurologic manifestations present in most MPS types. Intrathecal (IT) or intracerebroventricular (ICV) administration of the enzyme directly into the cerebrospinal fluid (CSF) has been proposed and experienced in clinical trials and in single cases.Areas covered: This paper briefly summarizes the development of ERT to treat LSDs, particularly MPS, the technical aspects related to its CSF administration, the experience obtained so far with the IT and ICV use in several MPS types and provides an expert opinion on this subject.Expert opinion: Treatment of neuropathic MPS remains a challenge. The results of ongoing trials may bring IT and ICV administration of ERT to clinical use in the coming years, making it a therapeutic option for the treatment of neuronopathic patients in several MPS types.
other
2026-03-31 | RNA-seq dataset of brain tissue from MPSIIIA (Sgsh D31N) mouse model following antisense oligonucleotide treatment
This dataset contains RNA sequencing (RNA-seq) data generated from brain tissue of a murine model of mucopolysaccharidosis type IIIA (MPSIIIA). The model used was B6.Cg-Sgsh^MPSIIIA/PstJ mice (Jackson Laboratories), which harbor a missense mutation in the murine Sgsh gene (c.91G>A, p.D31N). Homozygous mice exhibit approximately 3–4% of normal SGSH enzymatic activity, resulting in extensive lysosomal accumulation of heparan sulfate (HS) and progressive neurodegeneration. RNA was extracted from brain tissue of wild-type, disease-model (Sgsh homozygous), and antisense oligonucleotide (ASO)-treated mice. RNA-seq libraries were prepared using the MARS-seq protocol and sequenced on an Illumina NovaSeq platform, generating single-end reads (~26 million reads per sample). Raw sequencing data are provided as FASTQ files, along with accompanying sample metadata. This dataset enables analysis of differential gene expression and transcriptional signatures associated with MPSIIIA pathology, as well as transcriptional changes following ASO-mediated reduction of EXT1 expression. The dataset is associated with the study:“Antisense oligonucleotides mediated substrate reduction therapy ameliorates heparan sulfate accumulation in MPSIIIA models. All animal procedures were approved by the Sheba Medical Center IACUC.
2024-03-27 | Cellular Organelle-Related Transcriptomic Profile Abnormalities in Neuronopathic Types of Mucopolysaccharidosis: A Comparison with Other Neurodegenerative Diseases.
Mucopolysaccharidoses (MPS) are a group of diseases caused by mutations in genes encoding lysosomal enzymes that catalyze reactions of glycosaminoglycan (GAG) degradation. As a result, GAGs accumulate in lysosomes, impairing the proper functioning of entire cells and tissues. There are 14 types/subtypes of MPS, which are differentiated by the kind(s) of accumulated GAG(s) and the type of a non-functional lysosomal enzyme. Some of these types (severe forms of MPS types I and II, MPS III, and MPS VII) are characterized by extensive central nervous system disorders. The aim of this work was to identify, using transcriptomic methods, organelle-related genes whose expression levels are changed in neuronopathic types of MPS compared to healthy cells while remaining unchanged in non-neuronopathic types of MPS. The study was conducted with fibroblast lines derived from patients with neuronopathic and non-neuronopathic types of MPS and control (healthy) fibroblasts. Transcriptomic analysis has identified genes related to cellular organelles whose expression is altered. Then, using fluorescence and electron microscopy, we assessed the morphology of selected structures. Our analyses indicated that the genes whose expression is affected in neuronopathic MPS are often associated with the structures or functions of the cell nucleus, endoplasmic reticulum, or Golgi apparatus. Electron microscopic studies confirmed disruptions in the structures of these organelles. Special attention was paid to up-regulated genes, such as PDIA3 and MFGE8, and down-regulated genes, such as ARL6IP6, ABHD5, PDE4DIP, YIPF5, and CLDN11. Of particular interest is also the GM130 (GOLGA2) gene, which encodes golgin A2, which revealed an increased expression in neuronopathic MPS types. We propose to consider the levels of mRNAs of these genes as candidates for biomarkers of neurodegeneration in MPS. These genes may also become potential targets for therapies under development for neurological disorders associated with MPS and candidates for markers of the effectiveness of these therapies. Although fibroblasts rather than nerve cells were used in this study, it is worth noting that potential genetic markers characteristic solely of neurons would be impractical in testing patients, contrary to somatic cells that can be relatively easily obtained from assessed persons.
2023-09-11 | Identification of genetic variants associated with a wide spectrum of phenotypes clinically diagnosed as Sanfilippo and Morquio syndromes using whole genome sequencing
Mucopolysaccharidoses (MPSs) are inherited lysosomal storage disorders (LSDs). MPSs are caused by excessive accumulation of mucopolysaccharides due to missing or deficiency of enzymes required for the degradation of specific macromolecules. MPS I-IV, MPS VI, MPS VII, and MPS IX are sub-types of mucopolysaccharidoses. Among these, MPS III (also known as Sanfilippo) and MPS IV (Morquio) syndromes are lethal and prevalent sub-types. This study aimed to identify causal genetic variants in cases of MPS III and MPS IV and characterize genotype-phenotype relations in Pakistan. We performed clinical, biochemical and genetic analysis using Whole Genome Sequencing (WGS) in 14 Pakistani families affected with MPS III or MPS IV. Patients were classified into MPS III by history of aggressive behaviors, dementia, clear cornea and into MPS IV by short trunk, short stature, reversed ratio of upper segment to lower segment with a short upper segment. Data analysis and variant selections were made based on segregation analysis, examination of known MPS III and MPS IV genes, gene function, gene expression, the pathogenicity of variants based on ACMG guidelines and in silico analysis. In total, 58 individuals from 14 families were included in the present study. Six families were clinically diagnosed with MPS III and eight families with MPS IV. WGS revealed variants in MPS-associated genes including NAGLU, SGSH, GALNS, GNPTG as well as the genes VWA3B , BTD , and GNPTG which have not previously associated with MPS. One family had causal variants in both GALNS and BTD . Accurate and early diagnosis of MPS in children represents a helpful step for designing therapeutic strategies to protect different organs from permanent damage. In addition, pre-natal screening and identification of genetic etiology will facilitate genetic counselling of the affected families. Identification of novel causal MPS genes might help identifying new targeted therapies to treat LSDs.
2020-05-13 | Evading the AAV Immune Response in Mucopolysaccharidoses
The humoral immune response elicited by adeno-associated virus (AAV)-mediated gene therapy for the treatment of mucopolysaccharidoses (MPS) poses a significant challenge to achieving therapeutic levels of transgene expression. Antibodies targeting the AAV capsid as well as the transgene product diminish the production of glycosaminoglycan (GAG)-degrading enzymes essential for the treatment of MPS. Patients who have antibodies against AAV capsid increase in number with age, serotype, and racial background and are excluded from the clinical trials at present. In addition, patients who have undergone AAV gene therapy are often excluded from the additional AAV gene therapy with the same serotype, since their acquired immune response (antibody) against AAV will limit further efficacy of treatment. Several methods are being developed to overcome this immune response, such as novel serotype design, antibody reduction by plasmapheresis and immunosuppression, and antibody evasion using empty capsids and enveloped AAV vectors. In this review, we examine the mechanisms of the anti-AAV humoral immune response and evaluate the strengths and weaknesses of current evasion strategies in order to provide an evidence-based recommendation on evading the immune response for future AAV-mediated gene therapies for MPS.
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Drug Discovery Landscape
22 orphan drug designations for Sanfilippo syndrome type A, including 1 approved therapy.
22 orphan drug designations for Sanfilippo syndrome type A, including 1 approved therapy.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
N-sulfoglucosamine sulfohydrolase | proteins | FDA | Denali Therapeutics Inc. | |
Human heparan N-sulfatase, recombinant | proteins | EMA | 3R Pharma Consulting GmbH | |
Human N-sulfoglucosamine sulfohydrolase fused to a humanised monoclonal antibody targeting human transferrin receptor | proteins | FDA | JCR Pharmaceuticals Co., Ltd. | |
recombinant self-complementary adeno-associated virus9 gene therapy expressing codon-optimized human N-Sulfoglucosamine Sulfohydrolase gene | gene therapies | FDA | NeuroGT, Inc. | |
Recombinant Human Heparan N-sulfatase (rhHNS) | proteins | FDA | GC Biopharma Corp. | |
N-sulfoglucosamine sulfohydrolase fused to a humanised monoclonal antibody targeting human transferrin receptor | proteins | EMA | JCR Europe B.V. | |
Recombinant human insulin receptor monoclonal antibody-N-heparan sulfamidase fusion protein | proteins | FDA | — | ArmaGen, Inc. |
chemically modified recombinant sulfamidase | proteins | FDA | Swedish Orphan Biovitrum AB (publ) | |
Autologous CD34+ hematopoietic stem cells transduced with an hCD11b lentiviral vector encoding for the human N-sulfoglucosamine sulfohydrolase (SGSH) gene | gene therapies | FDA | Orchard Therapeutics Ltd. | |
Self-complementary adeno-associated viral vector serotype 9 containing the SGSH gene | gene therapies | EMA | Ultragenyx Netherlands B.V. | |
Chemically modified human recombinant sulfamidase | proteins | EMA | Swedish Orphan Biovitrum AB (publ) | |
recombinant adeno-associated virus vector serotype 9 expressing human N-Sulfoglucosamine Sulfohydrolase | gene therapies | FDA | — | Research Institute at Nationwide Children's Hospital |
adeno-associated viral (AAV) vector serotype rh. 10 encoding the human N-sulfoglycosamine sulphohydrolase cDNA (SGSH) | gene therapies | FDA | LYSOGENE | |
Adeno-associated viral vector serotype rh.10 carrying the human N-sulfoglucosamine sulfohydrolase cDNA | gene therapies | EMA | LYSOGENE | |
Autologous CD34+ cells transduced with a lentiviral vector containing the human SGSH gene | gene therapies | EMA | Orchard Therapeutics (Netherlands) B.V. | |
rebisufligene etisparvovec-hopf [Fayuvi] | gene therapies | FDA | Approved | Ultragenyx Pharmaceutical Inc. |
adeno associated viral vector serotype rh.10 carrying the human SGSH and SUMF1 cDNAs | gene therapies | FDA | Lysogene | |
Adeno-associated viral vector serotype 9 containing the human sulfamidase gene | gene therapies | EMA | Esteve Pharmaceuticals S.A. | |
adeno-associated virus vector serotype 9 expressing human sulfamidase | gene therapies | FDA | Esteve Pharmaceuticals, S.A. | |
Adenovirus-associated viral vector serotype 10 carrying the human N-sulfoglucosamine sulfohydrolase and sulfatase modifying factor 1 cDNAs | gene therapies | EMA | LYSOGENE | |
Human heparan N-sulfatase, recombinant | proteins | EMA | Shire Pharmaceuticals Ireland Limited | |
sulfamidase | gene therapies | FDA | Shire Human Genetic Therapies, Inc. |
“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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