Mucopolysaccharidosis type 1 (MPS1)


Description

MPS1 (MIM 252800) is an autosomal recessive lysosomal storage disorder, otherwise known as Hurler syndrome (severe) or Scheie syndrome (milder variant). The condition is caused by a deficiency of the enzyme alpha-L-iduronidase (IDUA), which is required for lysosomal degradation of the glycosaminoglycans, heparan sulphate and dermatan sulphate. Affected individuals have a characteristic pattern of urine metabolites and a deficiency in the IDUA enzyme activity. Biochemical enzyme analysis utilises these features to confirm a clinical diagnosis. Hurler patients are usually diagnosed by the age of 2 years and characteristically have short stature, coarse facial features, developmental delay, heart defects and hepatosplenomegaly, amongst their clinical symptoms. Scheie patients can present at a later age, and have a milder course of symptoms, including joint stiffness, corneal clouding and aortic valve disease. Other patients have an intermediate phenotype. The phenotypic heterogeneity correlates to some extent with the different nature of the mutations identified in the IDUA gene, although many novel mutations are known, there are �common� mutations within the gene. The IDUA gene (4p16.3) has 14 exons and mutations have been found throughout the gene. The recurrent mutations p.Gln70X, p.Ala327Pro and p.Trp402X account for approx. 70% of disease alleles in the Northern European population. The p.Trp402X and p.Gln70X are the most common mutations seen in Hurler patients. p.Arg89Gln and c.590-7G>A are generally associated with Scheie syndrome.

Also known as

Hurler syndrome, Scheie syndrome, Hurler-Scheie syndrome, MPS


Request a test

When requesting this test please use the referral form provided. Please also refer to any additional information provided for this test.


Additional information

Clinically affected patients should have their diagnosis confirmed by biochemical analysis; this should be arranged either locally or with the Enzyme Unit, Great Ormond Street Hospital. Biochemically confirmed patients can be referred for mutation analysis. If the necessary patient samples are unavailable genetic testing can be undertaken in the parents of a child. Level 1 Mutation Analysis: Detection of commonly reported mutations p.Gln70X, p.Ala327Pro and p.Trp402X by direct sequence analysis. Level 2 Mutation Analysis: Direct sequencing of all 14 coding exons and intron-exon boundaries. Download additional information >


Sending address

Great Ormond Street Hospital NE Thames Regional Genetics Service Laboratories
Great Ormond Street Hospital for Children
Barclay House
37 Queen Square
London
WC1N 3BH

Laboratory service

Genetics


Sample requirements

1ml EDTA neonates, 5ml EDTA adults


Reference range

Not applicable


Turnaround time

Common mutations - 20 days; gene screen - 40 days


Disease / group

IDUA


Cost

Upon request


Call in advance?

Prenatals must be arranged in advance, through a Clinical Genetics department if possible.


Genetics

The Genetics Laboratories provide an extensive range of Cytogenetics and Molecular Genetics diagnostic testing services.

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