CPT® Code 81166

BRCA1 (BRCA1, DNA repair associated) (eg, hereditary breast and ovarian cancer) gene analysis; full duplication/deletion analysis (ie, detection of large gene rearrangements)

The CPT® Code 81166 pertains to the molecular genetic testing of the BRCA1 gene, which is crucial for understanding hereditary breast and ovarian cancer risks. The BRCA1 gene, located on chromosome 17, plays a significant role in maintaining the integrity of genetic material by facilitating the repair of DNA damage. This gene is part of a family of genes that are responsible for the error-free repair of chromosomal damage and the resolution of DNA double-strand breaks. When mutations occur in the BRCA1 gene, its ability to repair damaged DNA is compromised, leading to uncontrolled cell proliferation, which can result in cancer development. Specifically, mutations in the BRCA1 gene are associated with an increased risk of early-onset breast and ovarian cancers in females, as well as a heightened risk for certain other cancers in both genders, including cervical, uterine, pancreatic, and colon cancers in females, and breast, pancreatic, and testicular cancers in males. Genetic testing for BRCA1 mutations is essential for identifying hereditary cancer syndromes, guiding treatment options, and assessing the risk for family members. The testing process typically involves analyzing whole blood or buccal cells. The full sequence analysis, represented by CPT® Code 81165, is utilized to compare gene segments for similarities and differences, which aids in identifying genetic relationships. This analysis examines various aspects of the gene, including active and post-translational modification sites, gene structures, the distribution of introns and exons, and regulatory elements. Additionally, genetic markers can be identified through the detection of point mutations or single nucleotide polymorphisms. CPT® Code 81166 specifically refers to the full duplication/deletion analysis, which is employed to detect large gene rearrangements that may not be identified through standard sequence analysis. In a normal genetic context, each cell should contain two copies of the BRCA1 gene, except for sex chromosomes. The presence of zero or one copy indicates a deletion variant, while three or more copies suggest a duplication variant. Furthermore, when testing for a known familial variant, as indicated by CPT® Code 81215, a specific site on the BRCA1 gene is analyzed for mutations that have already been identified in another family member, thereby providing critical information for genetic counseling and risk assessment.