Familial Hypercholesterolemia: LDLR Deletion/Duplication (MLPA)

Test Information

Turnaround Time

2 weeks

CPT Code(s)

81405

Cost

$500

Genes

Clinical Information

Familial hypercholesterolemia has an estimated prevalence of 1 in 200-250 individuals, and copy number variants in LDLR account for up to 10% of cases. This condition is associated with significant elevations in low-density lipoprotein (LDL) cholesterol. In addition, total cholesterol is typically increased (usually greater than 300 mg/dL in untreated individuals) with normal to slight elevations in triglycerides. Familial hypercholesterolemia is associated with increased risk of premature cardiovascular disease, specifically atherosclerosis, and symptoms include angina, heart attack, and rarely stroke. Other findings include a hazy ring along the outer rim of the iris known as corneal arcus and xanthomas, particularly of the hands and Achilles tendon.

Indications

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

Methodology

multiplex ligation-dependent probe amplification (MLPA)

Detection

Sequencing of the LDLR gene will detect mutations in approximately 90% of individuals with LDLR-related familial hypercholesterolemia. Of those with a normal sequencing result, approximately 10% will have a deletion or duplication identified by MLPA.

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.

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

Deletion/Duplication, Molecular Testing
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