Niemann-Pick Disease A/B: SMPD1 Sequencing

SMPD1 sequencing is a molecular test used to identify variants in the gene associated with Niemann-Pick A/B disease.

Turnaround Time

3 weeks

CPT Code(s)

81479

Cost

$800

Genes

• Niemann-Pick disease A/B

Patients with Niemann-Pick disease type A typically present in early childhood with hepatosplenomegaly, failure to thrive, cherry red macular spot, pulmonary infiltration and significant neurologic degeneration. Patients with Niemann-Pick disease type B have a later age of onset and present with hepatosplenomagaly and pulmonary infiltration, but have a milder or absent neurological phenotype. Foam cells can be detected in the bone marrow of patients with both subtypes.

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

This analysis includes full sequencing of the coding region of the SMPD1 gene. Greater than 95% of patients are expected to have a detectable sequence variant.

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. 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.