Mucopolysaccharidosis II (MPSII), Hunter Syndrome : IDS Sequencing

IDS sequencing is a molecular test used to identify variants in the gene associated with Mucopolysaccharidosis II (MPS II), Hunter Syndrome. This analysis also includes MLPA to identify copy number variants as well as analysis for the common inversion between IDS and IDS-2.

Turnaround Time

3 weeks

CPT Code(s)

81405

Cost

$1,000

Genes

Hunter syndrome is an X-linked lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase. Features include coarse facial appearance, short stature, hepatosplenomegaly, intellectual disability and joint stiffness. Typically, the disorder is diagnosed by enzymatic assay, however, the determination of carrier status using enzyme assay has proved problematic.

Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.

Sanger Sequencing

Sequencing of the gene will detect a mutation in 80-90% of individuals with Hunter syndrome. If no deleterious changes are identified, the laboratory will reflex to dosage studies via multiplex ligation-dependent probe amplification (MLPA) as well as checking for a specific inversion between IDS and IDS-2 at no additional cost.

The preferred sample type is peripheral blood collected in an EDTA (purple top) tube – at least 2-3ml for pediatric patients and 5-6ml for adult patients. Extracted DNA, dried blood spots, and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Prenatal diagnosis is available if the familial mutations are known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.