Early-onset Coronary Heart Disease/Familial Hypercholesterolemia: LDLR (Full Gene Sequencing)

CPT: 81406
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Test Details

Test Includes

This test covers all coding nucleotides of gene LDLR, plus at least two and typically 20 flanking intronic nucleotides upstream and downstream of each coding exon, covering the conserved donor and acceptor splice sites, as well as typically 20 flanking nucleotides in the 5′ and 3′ UTR.

Use

Confirm a clinical diagnosis of familial hypercholesterolemia; allow early diagnosis in family members, guiding use of pharmacological treatment in children

Limitations

This method does not reliably detect mosaic variants; large deletions; large duplications, inversions, or other rearrangements; or deep intronic variants. It may be affected by allele dropout, it may not allow determination of the exact numbers of T/A or microsatellite repeats, and it does not allow any conclusion as to whether two heterozygous variants are present on the same or on different chromosome copies.

This test was developed, and its performance characteristics determined, by LabCorp. It has not been cleared or approved by the US Food and Drug Administration (FDA). The FDA has determined that such clearance or approval is not necessary.

Methodology

DNA sequencing

Reference Interval

Normal equals reference sequence or variants that are known or predicted to be benign; abnormal equals all other variants.

Additional Information

Early-onset coronary artery disease (EO-CAD) is a common, progressive heart disease caused by atherosclerosis and is the leading cause of morbidity and mortality in the United States. A major risk factor for EO-CAD is hypercholesterolemia, a common lipid disorder, which is familial in about 10% cases. Mutations in LDLR account for >80% of familial hypercholesterolemia (FH), and mutation carriers typically have 90% to 100% risk of developing symptoms. Genetic testing can confirm a clinical diagnosis of FH/EO-CAD and allow for accurate identification of presymptomatic mutation carriers within affected families.

Specimen Requirements

Specimen

Whole blood; DNA is accepted (Call 866-647-0735 for DNA collection information.)

Volume

2 mL

Container

Lavender-top (EDTA) tube

Collection

Samples may be stored for brief periods at 4°C. Ship overnight at room temperature.

Storage Instructions

Maintain specimen at room temperature.

Causes for Rejection

Container broken or leaking; container not labeled or label not legible

Clinical Information

Special Instructions

In cases in which a known mutation can be documented, the physician may prefer to order test 252640.

Test orders must include an attestation that the provider has the patient's informed consent for genetic testing. See sample physician office consent form: Consent for Genetic Testing. In the case of family tests (ie, known mutations), Correlagen requires the result report of the first patient tested in the family (the index case), if not performed at Correlagen. Other family members are subsequently tested for the specific mutation found in the first patient tested.

References

Mayer B, Erdmann J, Schunkert H. Genetics and heritability of coronary artery disease and myocardial infarction, 2007. Clin Res Cardiol. 2007 Jan; 96(1):1-7. 17021678
Varret M, Abifadel M, Rabès JP, Boileau C. Genetic heterogeneity of autosomal dominant hypercholesterolemia. Clin Genet. 2008 Jan; 73(1):1-13. 18028451

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
252388 Early-Onset CHD:LDLR 252054 Routing 56159-7
252388 Early-Onset CHD:LDLR 252391 Early-Onset CHD:LDLR N/A

For Providers

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