Skip to content
30% Off: use code OCTOBER at checkout

Condition report · Metabolic

Mucopolysaccharidoses

Whole genome sequencing reads eleven genes linked to the mucopolysaccharidoses, including IDUA, IDS, GALNS and ARSB, for changes that cause a group of conditions in which sugar chains build up in tissues.

Updated 23 October 2026

Included in Premium and Premium + AI

Free shipping · Results in 6–8 weeks

Order with Premium

About this condition

A group of rare inherited conditions in which a missing enzyme stops the body breaking down glycosaminoglycans, long sugar chains that build up in tissues. This report covers IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, GLB1, ARSB, GUSB and HYAL1.

Mucopolysaccharidoses, often shortened to MPS, are a group of inherited conditions. Lysosomes are the parts of a cell that break down waste. In MPS, a lysosome lacks one working enzyme, so long sugar chains called glycosaminoglycans (GAGs) build up in cells and tissues over time. These sugar chains are found in connective tissue such as cartilage, bone and skin.

The types differ by which enzyme is missing and which sugar chain builds up. Each type is caused by changes in a different gene: IDUA (MPS I), IDS (MPS II), SGSH, NAGLU, HGSNAT and GNS (MPS III), GALNS (MPS IVA), GLB1 (MPS IVB), ARSB (MPS VI), GUSB (MPS VII) and HYAL1 (MPS IX). Most types are autosomal recessive, which means a child needs two changed copies of the gene, one from each parent. MPS II is X-linked recessive and mainly affects boys. Female carriers are usually free of symptoms.

Knowing the type matters because treatment differs. Enzyme replacement therapy, which gives the missing enzyme through a vein, and stem cell transplant are used for some types but not others. Knowing the gene involved also guides advice for other family members.

The 9 conditions we analyse

Mucopolysaccharidosis

A group of conditions in which lysosomes, the parts of a cell that break down waste, cannot clear glycosaminoglycans because an enzyme is missing or weak.

Signs and symptoms

Signs depend on the type but often include coarse facial features, stiff joints, hernias, heart valve changes and breathing problems. Some types also affect the brain, causing learning and behaviour problems.

What a diagnosis changes

Care involves several specialists, and enzyme replacement therapy or stem cell transplant is available for some types only.

Genes analysed

Also known as

MPS; Mucopolysaccharidoses

Specific forms also covered

  • Mucopolysaccharidosis Type I

    Autosomal recessive

    Caused by changes in IDUA, which makes alpha-L-iduronidase, an enzyme that breaks down heparan sulfate and dermatan sulfate.

    IDUA

  • Mucopolysaccharidosis Type II

    X-linked recessive

    Caused by changes in IDS on the X chromosome, which makes iduronate-2-sulfatase, an enzyme that breaks down heparan sulfate and dermatan sulfate.

    IDS

  • Mucopolysaccharidosis Type III

    Autosomal recessive

    Caused by changes in SGSH, NAGLU, HGSNAT or GNS, each of which makes an enzyme that breaks down heparan sulfate.

    GNS, HGSNAT, NAGLU, SGSH

  • Mucopolysaccharidosis Type IVA

    Autosomal recessive

    Caused by changes in GALNS, which makes N-acetylgalactosamine-6-sulfatase, an enzyme that breaks down keratan sulfate and chondroitin-6-sulfate.

    GALNS

  • Mucopolysaccharidosis Type IVB

    Autosomal recessive

    Caused by changes in GLB1, which makes beta-galactosidase, an enzyme that breaks down keratan sulfate; the same gene can cause GM1 gangliosidosis.

    GLB1

  • Mucopolysaccharidosis Type VI

    Autosomal recessive

    Caused by changes in ARSB, which makes arylsulfatase B, an enzyme that breaks down dermatan sulfate and chondroitin-4-sulfate.

    ARSB

  • Mucopolysaccharidosis Type VII

    Autosomal recessive

    Caused by changes in GUSB, which makes beta-glucuronidase, an enzyme that breaks down several sugar chains, including heparan sulfate and dermatan sulfate.

    GUSB

  • Mucopolysaccharidosis Type IX

    Autosomal recessive

    Caused by changes in HYAL1, which makes hyaluronidase-1, an enzyme that breaks down hyaluronan, a sugar chain found in soft connective tissue.

    HYAL1

Includes 22 related subtypes ↓
  • Hurler syndrome
  • Hurler-Scheie syndrome
  • Morquio syndrome C
  • mucopolysaccharidosis type 1
  • mucopolysaccharidosis type 2
  • mucopolysaccharidosis type 2, attenuated form
  • mucopolysaccharidosis type 2, severe form
  • mucopolysaccharidosis type 3
  • mucopolysaccharidosis type 3A
  • mucopolysaccharidosis type 3B
  • mucopolysaccharidosis type 3C
  • mucopolysaccharidosis type 3D
  • mucopolysaccharidosis type 4
  • mucopolysaccharidosis type 4A
  • mucopolysaccharidosis type 4B
  • mucopolysaccharidosis type 6
  • mucopolysaccharidosis type 6, rapidly progressing
  • mucopolysaccharidosis type 6, slowly progressing
  • mucopolysaccharidosis type 7
  • mucopolysaccharidosis type 9
  • mucopolysaccharidosis, type 10
  • Scheie syndrome
MONDO:0019249Orphanet 79213MedGen 7733Sources: [1][2][3]

Why whole genome sequencing

The gene involved decides the type, which affects treatment and the advice for relatives.

Eleven genes, one group of conditions

Changes in any of eleven genes can cause a mucopolysaccharidosis, and many types share symptoms such as stiff joints and coarse facial features. Whole genome sequencing reads these genes in one test.

Most types are recessive

Most types are autosomal recessive, so a person usually inherits a changed copy of the gene from both parents. MPS II is X-linked, so its pattern of inheritance in a family is different.

Treatment depends on the type

Enzyme replacement therapy and stem cell transplant are used for some of these types and not others, so the exact type shapes the choice of treatment.

Limitations

  • Mucopolysaccharidosis type X (ARSK), MPS-plus syndrome (VPS33A) and a possible type IIIE (ARSG) are not covered.
  • Only the eleven genes listed are read, so changes in other genes that cause similar symptoms are not covered.

References

  1. Lipiński P, Różdżyńska-Świątkowska A, Wiśniewska K, Rusecka J, Ługowska A, Żuber Z et al., 2025. Mucopolysaccharidoses-What Clinicians Need to Know: A Clinical, Biochemical, and Molecular Overview
  2. Leal AF, Prieto LE, Pachajoa H, Tomatsu S, 2025. Mucopolysaccharidosis VI: Therapeutic strategies and perspectives
  3. Fink SP, Triggs-Raine B, 2024. Genetic Deficiencies of Hyaluronan Degradation
  4. Clarke LA, 2002. Mucopolysaccharidosis Type I
  5. Scarpa M, Lampe C, 2007. Mucopolysaccharidosis Type II
  6. Aries C, Koehn A, Lindschau M, Muschol N, 2019. Mucopolysaccharidosis Type III
  7. Regier DS, Oetgen M, Tanpaiboon P, 2013. Mucopolysaccharidosis Type IVA
  8. Regier DS, Tifft CJ, Rothermel CE, 2013. GLB1-Related Disorders
  9. Sun A, Wang R, 2024. Mucopolysaccharidosis Type VII

More conditions

All conditions →

One test. A lifetime of answers.

One kit, sent to your home. Your entire genome sequenced at the clinical standard used for diagnostic decisions. Physician-ready reports delivered to your Genome Manager in 6–8 weeks — permanent and updated as science advances.

Order with Premium

Free shipping · Results in 6–8 weeks