Alpha-mannosidosis: MAN2B1 Sequencing

Turnaround Time

3 weeks

CPT Code(s)

81479

Cost

$1,500

Genes

• Alpha-mannosidosis

Alpha mannosidosis is an autosomal recessive lysosomal storage disorder (LSD) caused a deficiency of alpha-mannosidase enzyme activity. This condition demonstrates variable expressivity with three clinical phenotypes described as mild (type I), moderate (type II), and severe (type III), with onset varying from prenatal loss with type III to after 10 years of age with type I. Features can include mild or moderate intellectual disability, abnormalities in motor function, hearing loss, dysostosis multiplex, immunodeficiency, cataracts/corneal opacities, hepatosplenomegaly, and characteristic facial features.

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

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.