CPT® Code 81298

MSH6 (mutS homolog 6 [E. coli]) (eg, hereditary non-polyposis colorectal cancer, Lynch syndrome) gene analysis; full sequence analysis

The CPT® Code 81298 pertains to the molecular genetic testing of the MSH6 gene, which is crucial for identifying specific mutations that may increase an individual's risk of developing hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome. The MSH6 gene is located on chromosome 2 and plays a vital role in the DNA repair process. It is part of a protein complex that works alongside the MSH1/PMS2 complex to detect and correct errors that occur during DNA replication. When these errors are not repaired, they can accumulate over time, leading to uncontrolled cell growth and the formation of tumors. HNPCC is the most prevalent cancer associated with mutations in the MSH6 gene, but such mutations can also lead to cancers in other organs, including the endometrium, ovaries, prostate, stomach, small intestine, liver, gallbladder duct, upper urinary tract, brain, and skin. The presence of MSH6 mutations is particularly significant in individuals with Lynch syndrome, which is found in approximately 10 percent of those diagnosed with HNPCC. This condition is characterized by an increased risk of developing various cancers, particularly colorectal and endometrial cancers, often at an older age. The MSH6 gene mutation is associated with a higher incidence of endometrial cancers compared to mutations in other related genes, such as MLH1 and MSH2. Additionally, specific mutations have been identified with greater frequency in Ashkenazi Jewish populations, with affected individuals typically experiencing the onset of tumors later in life. The full sequence analysis performed under CPT® Code 81298 involves comparing segments of the MSH6 gene to identify any mutations, including point mutations or single nucleotide polymorphisms, which are the most common types of alterations observed. This analysis is essential for understanding the genetic predisposition to cancer and guiding further testing and counseling for family members who may also be at risk.