Mucopolysaccharidosis III: Molecular basis and treatment.
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ABSTRACT:
SUBMITTER: Spahiu L
PROVIDER: S-EPMC10228206 | biostudies-literature | 2021
REPOSITORIES: biostudies-literature
Publications
Mucopolysaccharidosis III: Molecular basis and treatment.
Spahiu Lidvana L Behluli Emir E Peterlin Borut B Nefic Hilada H Hadziselimovic Rifat R Liehr Thomas T Temaj Gazmend G
Pediatric endocrinology, diabetes, and metabolism 20210101 3
Mucopolysaccharidoses (MPSs) are known as rare genetic diseases which are caused by mutation in the enzyme heparin sulfate, which normally leads to degradation and accumulation of glycosaminoglycans in the cells. There are 11 types of MPSs, whereby neuropathy may occur in seven of them (MPS I, II, IIIA, IIIB, IIIC, IIID and VII). Accumulation of degraded heparin sulfate in lysosomes causes cellular dysfunction and malfunction of several organs. However, the exact molecular mechanism how protein ...[more]
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Project description:BackgroundMucopolysaccharidosis type III is a progressive, neurodegenerative lysosomal storage disorder for which there is currently no effective therapy. Though numerous potential therapies are in development, there are several challenges to conducting clinical research in this area. We seek to make recommendations on the approach to clinical research in MPS III, including the selection of outcome measures and trial endpoints, in order to improve the quality and impact of research in this area.ResultsAn international workshop involving academic researchers, clinical experts and industry groups was held in June 2015, with presentations and discussions on disease pathophysiology, biomarkers, potential therapies and clinical outcome measures. A set of recommendations was subsequently prepared by a working group and reviewed by all delegates. We present a series of 11 recommendations regarding the conduct of clinical research, outcome measures and management of natural history data in Mucopolysaccharidosis type III.ConclusionsImproving the quality of clinical research in Mucopolysaccharidosis type III will require an open, collaborative and systematic approach between academic researchers, clinicians and industry. Natural history data should be published as soon as possible and ideally collated in a central repository. There should be agreement on outcome measures and instruments for evaluation of clinical outcomes to maximise the effectiveness of current and future clinical research.
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Project description:Mucopolysaccharidosis type IIIC or Sanfilippo syndrome type C (MPS IIIC, MIM #252930) is an autosomal recessive disorder caused by deficiency of the lysosomal membrane enzyme, heparan sulfate acetyl-CoA: alpha-glucosaminide N-acetyltransferase (HGSNAT, EC 2.3.1.78), which catalyses transmembrane acetylation of the terminal glucosamine residues of heparan sulfate prior to their hydrolysis by alpha-N-acetylglucosaminidase. Lysosomal storage of undegraded heparan sulfate in the cells of affected patients leads to neuronal death causing neurodegeneration and is accompanied by mild visceral and skeletal abnormalities, including coarse facies and joint stiffness. Surprisingly, the majority of MPS IIIC patients carrying missense mutations are as severely affected as those with splicing errors, frame shifts or nonsense mutations resulting in the complete absence of HGSNAT protein.In order to understand the effects of the missense mutations in HGSNAT on its enzymatic activity and biogenesis, we have expressed 21 mutant proteins in cultured human fibroblasts and COS-7 cells and studied their folding, targeting and activity. We found that 17 of the 21 missense mutations in HGSNAT caused misfolding of the enzyme, which is abnormally glycosylated and not targeted to the lysosome, but retained in the endoplasmic reticulum. The other 4 mutants represented rare polymorphisms which had no effect on the activity, processing and targeting of the enzyme. Treatment of patient cells with a competitive HGSNAT inhibitor, glucosamine, partially rescued several of the expressed mutants. Altogether our data provide an explanation for the severity of MPS IIIC and suggest that search for pharmaceutical chaperones can in the future result in therapeutic options for this disease.
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Project description:BackgroundMucopolysaccharidosis type III (MPS III) is an autosomal recessive lysosomal storage disorder characterised by progressive neurocognitive deterioration. MPS III subtypes are clinically indistinguishable, with a wide range of symptoms and variable severity. The natural history of this disorder within an Asian population has not yet been extensively studied. This study investigated the natural history of Korean patients with MPS III.MethodsThirty-four patients from 31 families diagnosed with MPS III from January 1997 to May 2020 in Samsung Medical Centre were enrolled. Clinical, molecular, and biochemical characteristics were retrospectively collected from the patients' medical records and via interviews.Results18 patients had MPS IIIA, 14 had IIIB, and two had IIIC. Twenty (58.9%) patients were male. Mean age at symptom onset was 2.8 ± 0.8 years and at diagnosis was 6.3 ± 2.2 years. All patients with MPS IIIA and IIIB were classified into the rapidly progressing (RP) phenotype. The most common symptom at diagnosis was language retardation (88.2%), followed by motor retardation (76.5%), general retardation (64.7%), and hyperactivity (41.2%). Language retardation was more predominant in IIIA, and motor retardation was more predominant in IIIB. The mean age of the 13 deceased patients at the time of the study was 14.4 ± 4.1 years. The age at diagnosis and lag time were significantly older and longer in the non-survivor group compared with the survivor group (p = 0.029 and 0.045, respectively). Genetic analysis was performed in 24 patients with MPS III and identified seven novel variants and three hot spots.ConclusionThis study is the first to analyse the genetic and clinical characteristics of MPS III patients in Korea. Better understanding of the natural history of MPS III might allow early diagnosis and timely management of the disease and evaluation of treatment outcomes in future clinical trials for MPS III.
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Project description:Mucopolysaccharidosis type III (MPS III) or Sanfilippo disease is an orphan inherited lysosomal storage disease and one of the most common MPS subtypes. The classical presentation is an infantile-onset neurodegenerative disease characterised by intellectual regression, behavioural and sleep disturbances, loss of ambulation, and early death. Unlike other MPS, no disease-modifying therapy has yet been approved. Here, we review the numerous approaches of curative therapy developed for MPS III from historical ineffective haematopoietic stem cell transplantation and substrate reduction therapy to the promising ongoing clinical trials based on enzyme replacement therapy or adeno-associated or lentiviral vectors mediated gene therapy. Preclinical studies are presented alongside the most recent translational first-in-man trials. In addition, we present experimental research with preclinical mRNA and gene editing strategies. Lessons from animal studies and clinical trials have highlighted the importance of an early therapy before extensive neuronal loss. A disease-modifying therapy for MPS III will undoubtedly mandate development of new strategies for early diagnosis.
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Project description:PurposeMucopolysaccharidosis type II (MPS II) is a rare X-linked lysosomal storage disorder caused by genetic alterations in the iduronate 2-sulfatase (IDS) gene. A wide range of variants has been reported for different countries and ethnic groups. We collected, analyzed and uniformly summarized all published IDS gene variants reported in literature up to June 2023, here providing the first worldwide review and classification.MethodsData was obtained from a literature search, conducted in PubMed and Google. All data was analyzed to define the most common alleles, geographic distribution and genotype-phenotype correlation. Moreover, point variants were classified according to their pathogenicity, based on the ACMG guidelines.ResultsSeveral types of variants have been described in the IDS gene, including intrachromosomal homologous recombination occurring between the homologous regions of IDS gene and its pseudogene IDSP1. Overall, we collected 2852 individuals from 2798 families, including 24 female patients. Most families carried missense variants, followed by large deletions-insertions and complex rearrangements, small frameshift deletions/insertions and nonsense variants. Based on ACMG guidelines, 62.9% of the 779 point variants were classified as "pathogenic", 35.4% as "likely pathogenic", and the remaining 13 variants as having "uncertain significance".ConclusionData from this study confirmed that MPS II is a genetically very heterogeneous disorder, making genotype-phenotype correlation very challenging and in most cases merely unfeasible. Mutation updates are essential for the correct molecular diagnosis, genetic counseling, prenatal and preimplantation diagnosis, and disease management.
| S-EPMC11610362 | biostudies-literature
Project description:Mucopolysaccharidosis type II (Hunter syndrome) is an X linked lysosomal storage disorder resulting from heterogeneous mutations in the iduronate-2-sulphatase (IDS) gene. To detect IDS gene mutations, direct sequencing of IDS cDNA fragments coupled with assays on IDS genomic amplicons was applied to 18 unrelated patients with MPS II. Seventeen mutations were detected from the 18 patients including seven missense mutations (S71R, A82E, A85T, R88C, R468W, R468Q, and E521V), five deletions (alphaR95, 383delAT, 596delAACA, 1148delC, and 1216delCT), two insertions (208insC and 1063insA), two splicing mutations (1006+5g-->c in intron 7, 1122C-->T in exon 8), and an intragenic deletion of IDS exons 4, 5, 6, and 7. Nine of the small mutations were novel mutations. Mutation 596del-AACA was detected in two unrelated patients. The mutation in intron 7 was found to cause aberrant splicing and resulted in a 22 bp insertion into its mRNA transcript. The intragenic deleted IDS gene expressed two aberrant mRNA transcripts consisting of exons 1-2-8-9 and 3-8-9. Analysis of mutations A85T, R88C, R468Q, R468W, and 438C/T found no polymorphism for the four missense mutations but about 36% heterozygosity for the 438C/T silent mutation. These results provide further evidence of mutational heterogeneity for MPS II. Also, underlying sequence directed mutagenesis mechanisms for some recurrent mutations in the IDS gene were proposed.
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Project description:Mucopolysaccharidosis (MPS) VII is a lysosomal storage disorder characterized by deficient activity of β-glucuronidase, leading to progressive accumulation of incompletely degraded heparan, dermatan and chondroitin sulfate glycosaminoglycans (GAGs). Patients with MPS VII exhibit progressive skeletal deformity including kyphoscoliosis and joint dysplasia, which decrease quality of life and increase mortality. Previously, using the naturally-occurring canine model, we demonstrated that one of the earliest skeletal abnormalities to manifest in MPS VII is failed initiation of secondary ossification in vertebrae and long bones at the requisite postnatal developmental stage. The objective of this study was to obtain global insights into the molecular mechanisms underlying this failed initiation of secondary ossification using whole transcriptome sequencing (RNA-Seq). Epiphyseal tissue was isolated from the vertebrae of control and MPS VII affected dogs at 9 and 14 days-of-age (n=5 for each group). Differences in global gene expression across this developmental window for both cohorts were established using RNA-Seq. A targeted analysis focused on signaling pathways important in the regulation of endochondral ossification, and a subset of gene expression changes were validated using qPCR. Principal Component Analysis revealed clustering of samples from each group, indicating clear effects of both age and disease state. At 9 days-of-age, 1375 genes were significantly differentially expression between MPS VII and control, and by 14 days-of-age, this increased to 4719 genes. Osteoactivin (GPNMB) was the top upregulated gene in MPS VII at both ages. Targeted analysis revealed temporal changes in gene expression from 9 to 14 days-of-age in control samples consistent with chondrocyte maturation, cartilage resorption, and osteogenesis. In MPS VII samples, however, elements of key osteogenic pathways such as Wnt/β-catenin and BMP signaling were dysregulated. In conclusion, this study represents the first step towards identifying druggable therapeutic targets and putative biomarkers for bone disease in MPS VII patients during postnatal growth.
2020-07-01 | GSE130088 | GEO