Adrenoleukodystrophy, X-linked : ABCD1 Sequencing

Test Information

ABCD1 sequencing is a molecular test used to identify variants in the gene associated with X-linked Adrenoleukodystrophy.

Turnaround Time

3 weeks

CPT Code(s)

81405

Cost

$1,000

Genes

Clinical Information

X-linked adrenoleukodystrophy is a neurological disorder characterized by MRI findings in the white matter and adrenal cortex and abnormal plasma concentrations of very long chain fatty acids. The condition can present in three different phenotypes, childhood cerebral form, adrenomyeloneuropathy, and Addison disease only.

The childhood cerebral form has an onset of symptoms between ages 4-8 beginning with ADHD like symptoms with progressive cognitive, behavior, vision, hearing, and motor deterioration. Adrenomyeloneuropathy will usually present in males in their late twenties as sexual dysfunction, progressive paraparesis, sphincter disturbances and abnormalities in adrenocortical function. The mildest presentation is primary adrenocortical insufficiency without significant neurological involvement with onset ranging from two years to adulthood. Some carrier females may experience mild adrenomyeloneuropathy symptoms with a later age of onset.

Indications

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.

Methodology

Sanger Sequencing

Detection

Sequencing of the ABCD1 gene will detect a mutation in about 99% of affected males and about 93% of carrier females.

Specimen Requirements

5 to 7 ml of peripheral blood collected in an EDTA (lavender top) tube is the preferred specimen type. The minimal blood needed for reliable DNA isolation is 3 ml. Extracted DNA, dried blood spots, and saliva are also accepted for this test.

Transport Instructions

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 Testing Information

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.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Molecular Testing, Newborn Screening Follow-Up, Sanger Sequencing
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