Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (748 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Group of lysosomal storage diseases each caused by an inherited deficiency of an enzyme involved in the degradation of glycosaminoglycans (mucopolysaccharides). The diseases are progressive and often display a wide spectrum of clinical severity within one enzyme deficiency.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Mucopolysaccharidosis.
Where it fits in the MeSH classification
- Broader topics
- Carbohydrate Metabolism, Inborn Errors; Lysosomal Storage Diseases; Mucinoses
- Narrower topics
- Mucopolysaccharidosis I; Mucopolysaccharidosis II; Mucopolysaccharidosis III; Mucopolysaccharidosis IV; Mucopolysaccharidosis VI; Mucopolysaccharidosis VII
Research landscape
PubMed indexes 7,440 records tagged with the MeSH heading “Mucopolysaccharidoses” (counts retrieved 2026-10-29). 1,003 of them (13.5%) were published from 2020 onward, and the busiest period so far is through 1999 with 3,660 records.
Reviews account for 799 records (10.7%) and meta-analyses for 11. Randomized controlled trials number 46 (0.6%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 3,660 |
| 2000-2009 | 1,039 |
| 2010-2019 | 1,738 |
| 2020 onward | 1,003 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 799 | 10.7% |
| Meta-analyses | 11 | 0.1% |
| Randomized controlled trials | 46 | 0.6% |
Method: PubMed query "Mucopolysaccharidoses"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in rare and inherited diseases
Rare conditions are difficult to study: few patients means small studies, case reports and registries are common, and randomized trials are the exception. Small samples limit precision and can exaggerate effects, and cases reported in the literature may be the most severe or unusual. Evidence from many small studies is best read together. Check how patients were identified, how many were included and how long they were followed.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Self-inactivating, all-in-one AAV vectors for precision Cas9 genome editing via homology-directed repair in vivo | 2021 | Research article Design not recorded in structured metadata | 101 | cc by PMID 34725353 · DOI · PMC8560862 |
| Molecular architecture determines brain delivery of a transferrin receptor-targeted lysosomal enzyme | 2022 | Research article Design not recorded in structured metadata | 77 | cc by PMID 35226042 · DOI · PMC8932535 |
| Mucopolysaccharidosis Type I: Current Treatments, Limitations, and Prospects for Improvement | 2021 | Review article Design not recorded in structured metadata | 75 | cc by PMID 33572941 · DOI · PMC7911293 |
| Carpal tunnel syndrome in mucopolysaccharidosis type I: clinical, surgical and histopathological findings | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 41656624 · DOI · PMC13090557 |
Self-inactivating, all-in-one AAV vectors for precision Cas9 genome editing via homology-directed repair in vivo [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Adeno-associated virus (AAV) vectors are important delivery platforms for therapeutic genome editing but are severely constrained by cargo limits.
- Closing excerpt
- These results will enable the engineering of single-vector AAVs that can achieve diverse therapeutic genome editing outcomes.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (146 words)
Adeno-associated virus (AAV) vectors are important delivery platforms for therapeutic genome editing but are severely constrained by cargo limits. Simultaneous delivery of multiple vectors can limit dose and efficacy and increase safety risks. Here, we describe single-vector, ~4.8-kb AAV platforms that express Nme2Cas9 and either two sgRNAs for segmental deletions, or a single sgRNA with a homology-directed repair (HDR) template. We also use anti-CRISPR proteins to enable production of vectors that self-inactivate via Nme2Cas9 cleavage. We further introduce a nanopore-based sequencing platform that is designed to profile rAAV genomes and serves as a quality control measure for vector homogeneity. We demonstrate that these platforms can effectively treat two disease models [type I hereditary tyrosinemia (HT-I) and mucopolysaccharidosis type I (MPS-I)] in mice by HDR-based correction of the disease allele. These results will enable the engineering of single-vector AAVs that can achieve diverse therapeutic genome editing outcomes.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 34725353 · DOI · PMC8560862
Molecular architecture determines brain delivery of a transferrin receptor-targeted lysosomal enzyme [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Delivery of biotherapeutics across the blood-brain barrier (BBB) is a challenge.
- Closing excerpt
- These results highlight important features likely to impact the clinical development of TfR-targeting platforms in MPS II and potentially other CNS diseases.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (158 words)
Delivery of biotherapeutics across the blood-brain barrier (BBB) is a challenge. Many approaches fuse biotherapeutics to platforms that bind the transferrin receptor (TfR), a brain endothelial cell target, to facilitate receptor-mediated transcytosis across the BBB. Here, we characterized the pharmacological behavior of two distinct TfR-targeted platforms fused to iduronate 2-sulfatase (IDS), a lysosomal enzyme deficient in mucopolysaccharidosis type II (MPS II), and compared the relative brain exposures and functional activities of both approaches in mouse models. IDS fused to a moderate-affinity, monovalent TfR-binding enzyme transport vehicle (ETV:IDS) resulted in widespread brain exposure, internalization by parenchymal cells, and significant substrate reduction in the CNS of an MPS II mouse model. In contrast, IDS fused to a standard high-affinity bivalent antibody (IgG:IDS) resulted in lower brain uptake, limited biodistribution beyond brain endothelial cells, and reduced brain substrate reduction. These results highlight important features likely to impact the clinical development of TfR-targeting platforms in MPS II and potentially other CNS diseases.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 35226042 · DOI · PMC8932535
Mucopolysaccharidosis Type I: Current Treatments, Limitations, and Prospects for Improvement [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Mucopolysaccharidosis type I (MPS I) is a lysosomal disease, caused by a deficiency of the enzyme alpha-L-iduronidase (IDUA).
- Closing excerpt
- Finally, we highlight alternative and emerging treatments for the most common disease manifestations.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (183 words)
Mucopolysaccharidosis type I (MPS I) is a lysosomal disease, caused by a deficiency of the enzyme alpha-L-iduronidase (IDUA). IDUA catalyzes the degradation of the glycosaminoglycans dermatan and heparan sulfate (DS and HS, respectively). Lack of the enzyme leads to pathologic accumulation of undegraded HS and DS with subsequent disease manifestations in multiple organs. The disease can be divided into severe (Hurler syndrome) and attenuated (Hurler-Scheie, Scheie) forms. Currently approved treatments consist of enzyme replacement therapy (ERT) and/or hematopoietic stem cell transplantation (HSCT). Patients with attenuated disease are often treated with ERT alone, while the recommended therapy for patients with Hurler syndrome consists of HSCT. While these treatments significantly improve disease manifestations and prolong life, a considerable burden of disease remains. Notably, treatment can partially prevent, but not significantly improve, clinical manifestations, necessitating early diagnosis of disease and commencement of treatment. This review discusses these standard therapies and their impact on common disease manifestations in patients with MPS I. Where relevant, results of animal models of MPS I will be included. Finally, we highlight alternative and emerging treatments for the most common disease manifestations.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 33572941 · DOI · PMC7911293
Carpal tunnel syndrome in mucopolysaccharidosis type I: clinical, surgical and histopathological findings [4]
Abstract reading summary — source excerpts
- Opening excerpt
- IntroductionMucopolysaccharidosis type I is a rare metabolic disorder characterized by the accumulation of glycosaminoglycans, leading to musculoskeletal disorders such as carpal tunnel syndrome.
- Closing excerpt
- Level of evidenceIII.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (261 words)
IntroductionMucopolysaccharidosis type I is a rare metabolic disorder characterized by the accumulation of glycosaminoglycans, leading to musculoskeletal disorders such as carpal tunnel syndrome. This retrospective cohort study was performed to determine the prevalence and timing of the development of carpal tunnel syndrome, assess the efficacy of surgery on recurrence and the effect of haematopoietic stem cell transplantation in resolving accumulated degradation products.MethodsThirty-three mucopolysaccharidosis type I patients, born between 2001 and 2023, were included in this study. They received annual screening and treatment at our specialist hospital. Patient demographics, clinical symptoms of carpal tunnel syndrome pre- and post-carpal tunnel release and histopathological sections of the flexor retinaculum were collected. Regression analyses were conducted to assess cumulative risks and determine hazard ratios and survival curves were plotted.ResultsTwenty-seven of 33 mucopolysaccharidosis type I patients, with a median age at the latest follow-up of 13 years (IQR 7.7 to 18.3), were diagnosed with carpal tunnel syndrome on electrophysiological tests or ultrasound at a median age of 3.6 years (IQR 2.8 to 5.2). Only a few patients exhibited clinical symptoms. Twenty-one patients underwent carpal tunnel release and 13 patients experienced recurrence. The highest risk of developing carpal tunnel syndrome was within the first 6 years of life. Eight of the 11 patients accumulated degradation products within lysosomes despite successful haematopoietic stem cell transplantation.ConclusionsIn this study, 27 mucopolysaccharidosis type I patients were diagnosed with carpal tunnel syndrome, showing a high-risk window from 0 to 6 years of age. Recurrence of carpal tunnel syndrome after carpal tunnel release surgery was common, occurring in 61.9% of patients.Level of evidenceIII.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41656624 · DOI · PMC13090557
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Overview of the mucopolysaccharidoses [5]
- Research article Mucopolysaccharidosis I: management and treatment guidelines [6]
- Research article Mucopolysaccharidosis VI [7]
- Research article Cardiac disease in patients with mucopolysaccharidosis: presentation, diagnosis and management [8]
- Research article Recognition and diagnosis of mucopolysaccharidosis II (Hunter syndrome) [9]
- Research article Possible strategies to cross the blood-brain barrier [10]
References
- Ibraheim R, Tai PWL, Mir A, Javeed N, Wang J, Rodríguez TC, et al.. Self-inactivating, all-in-one AAV vectors for precision Cas9 genome editing via homology-directed repair in vivo. . 2021. PMID 34725353 · DOI · PMC8560862
- Arguello A, Mahon CS, Calvert MEK, Chan D, Dugas JC, Pizzo ME, et al.. Molecular architecture determines brain delivery of a transferrin receptor-targeted lysosomal enzyme. . 2022. PMID 35226042 · DOI · PMC8932535
- Hampe CS, Wesley J, Lund TC, Orchard PJ, Polgreen LE, Eisengart JB, et al.. Mucopolysaccharidosis Type I: Current Treatments, Limitations, and Prospects for Improvement. . 2021. PMID 33572941 · DOI · PMC7911293
- van Binsbergen BAW, van Dongen JA, Vriend L, Goedee SH, van Hasselt PM, Mink van der Molen AB. Carpal tunnel syndrome in mucopolysaccharidosis type I: clinical, surgical and histopathological findings. . 2026. PMID 41656624 · DOI · PMC13090557
- Muenzer J. Overview of the mucopolysaccharidoses. Rheumatology (Oxford). 2011. PMID 22210669 · DOI
- Muenzer J, Wraith JE, Clarke LA, International Consensus Panel on Management and Treatment of Mucopolysaccharidosis I. Mucopolysaccharidosis I: management and treatment guidelines. Pediatrics. 2009. PMID 19117856 · DOI
- Valayannopoulos V, Nicely H, Harmatz P, Turbeville S. Mucopolysaccharidosis VI. Orphanet J Rare Dis. 2010. PMID 20385007 · DOI · PMC2873242
- Braunlin EA, Harmatz PR, Scarpa M, Furlanetto B, Kampmann C, Loehr JP, et al.. Cardiac disease in patients with mucopolysaccharidosis: presentation, diagnosis and management. J Inherit Metab Dis. 2011. PMID 21744090 · DOI · PMC3228957
- Martin R, Beck M, Eng C, Giugliani R, Harmatz P, Muñoz V, et al.. Recognition and diagnosis of mucopolysaccharidosis II (Hunter syndrome). Pediatrics. 2008. PMID 18245410 · DOI
- Bellettato CM, Scarpa M. Possible strategies to cross the blood-brain barrier. Ital J Pediatr. 2018. PMID 30442184 · DOI · PMC6238258
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.