Copper Transport Disorders: ATP7A Sequencing

Turnaround Time

6 weeks

CPT Code(s)

81479

Cost

$1,500

Genes

Mutations in the ATP7A gene can manifest as three distinct phenotypes related to copper transport dysfunction and are inherited in an X-linked manner. Related biochemical findings are usually present in Menkes disease and Occipital horn syndrome but not in the distal motor neuropathy phenotype. Individuals with Menkes disease usually become symptomatic around 2-3 months of age. These infants may present with regression of milestones, seizures, hypotonia, failure to thrive, and characteristic changes of the hair. The primary features of occipital horn syndrome include specific bony changes at the site of muscle attachment to the occipital bone. These individuals may have other findings as well including bladder diverticula, inguinal hernias, and lax joints and skin with either normal or slightly reduced intellect. The related distal motor neuropathy is typically progressive, adult-onset with distal muscle weakness and atrophy in feet and hands. Absent ankle reflexes are common.

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 ATP7A gene is expected to detect a mutation in about 80% of individuals with one of the above phenotypes.

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.