Mucopolysaccharidosis I (MPS I) is an autosomal recessive lysosomal storage disorder that results from the deficiency of the enzyme a -L-iduronidase. This enzyme removes the non-reducing terminal a-L-iduronide residues during the lysosomal degradation of heparan sulphate and dermatan sulphate and its deficiency leads to an accumulation of these glycosaminoglycans. MPS I is seen in all populations at a frequency of approximately 1:100,000 for the severe form and 1:500,000 for the attenuated form. IDUA is the only gene currently known to be associated with MPS I. Sequence analysis of the coding region of the IDUA gene is available on a clinical basis at the Medical Genetics Laboratories at Baylor College of Medicine.

Reasons for Referral:

• Confirmation of a clinical diagnosis of Mucopolysaccharidosis type I .
• Carrier testing for individuals with a positive family history for an IDUA point mutation (molecular analysis of the affected relative is recommended).
• Prenatal diagnosis (known mutations only).

Testing Methodology:

PCR amplification of the exons contained in the IDUA gene coding region will be performed on patient genomic DNA. Direct sequencing of amplification products is performed in both the forward and reverse directions using automated fluorescence dideoxy sequencing methods.

Specimen Requirements:

Blood: EDTA (purple-top) tubes: Adults: 14 cc; Child: 6 cc; Infant: 2-3 cc
Requisition form must accompany the specimen. Prior to any genetic testing, we recommend genetic counseling and we request that the subject sign our consent statement and submit it with the sample. To receive forms, additional information or specimen collection kits, please contact the laboratory. Please call laboratory for specific requirements for prenatal testing.

Turnaround Time:

Index: 4 weeks

CPT Codes and Prices:

Index: 83891, 83898x14, 83894, 83904x28, 83909x28, 83912
Known Familial Mutation: 83891, 83898, 83894, 83904x2, 83909x2, 83912

References:

1. Meikle PJ, Hopwood JJ, Clague AE, Carey WF (1999) Prevalence of lysosomal storage disorders. JAMA 281: 249-54.
2. Poorthuis BJ, Wevers RA, Kleijer WJ, Groener JE, de Jong JG, van Weely S, Niezen-Koning KE, van Diggelen OP (1999) The frequency of lysosomal storage diseases in The Netherlands. Hum. Genet 105: 151-6.

Shipping Information

Forms:

 >> Gene Sequencing Requisition
 >> Prenatal Requisition

Test Codes:

Index: 6385
Known Familial Mutation: 6386
Prenatal (Known Familial Mutation Only): 6387

Medical Genetics Laboratories
Baylor College of Medicine · Houston, TX 77030
Phone: 1-800-411-GENE · Fax: 713-798-6584
E-mail: