Mucopolysaccharidosis II

Introduction

MPS II (Hunter Syndrome OMIM 309900) is an X-linked recessive mucopolysaccharide storage disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulphatase. This deficiency results in the accumulation of heparan and dermatan sulphates. MPS II is a multisystemic disorder characterised by facial dysmorphism, dysostosis multiplex and neurological deterioration. Death usually occurs during the second decade. Milder forms of the disorder show slower progression of somatic features and absence of neurological problems. The classification into mild and severe forms is somewhat artificial as the disorder exhibits a wide spectrum of clinical severity, defined by the underlying genetic mutation. The iduronate sulphatase gene (IDS) is situated on the X chromosome at Xq28 spanning 24 kb and encompassing 9 exons that encode a preproprotein of 550 amino acids.

Referral information

This service is funded by the National Commissioning Group (NCG). Samples received from England, Northern Ireland and Scotland are charged to NCG with the majority of samples being received from The Willink Metabolic Unit. New patients are initially diagnosed by enzyme analysis, therefore patients will usually have already been referred to a relevant NCG centre before DNA analysis is requested. Funding from the NCG also covers carrier detection, by DNA analysis, for family members.

Price & reporting times

Test Price NHS (£) Price non- NHS (£ ) TRT (calendar days)
Mutation scanning POA POA 56
Single mutation test POA POA 28
Urgent/Predictive single mutation test POA POA 14

Test validation & quality assurance - information for users

82% of affected patients will have a mutation detected by sequence analysis. 9% of patients will have a larger deletion or duplication detected by MLPA analysis. Another 9% will have a complex re-arrangement primarily the result of recombination between the functional gene and a pseudogene (IDSP1).

The laboratory is UKAS assessed against ISO 15189 standards.

Sample requirements

4ml EDTA blood sample. If Willink laboratory testing is required, a 10ml urine sample is required

Referral guidelines

Please see our referral guidelines for more information.

OMIM Number(s) - 309900

Gene(s) - IDS

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