CPT® Code 81292

MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) (eg, hereditary non-polyposis colorectal cancer, Lynch syndrome) gene analysis; full sequence analysis

The CPT® Code 81292 pertains to the molecular genetic testing of the MLH1 gene, which is crucial for identifying mutations that increase the risk of developing colorectal cancer and other associated cancers. The MLH1 gene, located on chromosome 3, plays a vital role in encoding proteins responsible for DNA repair. When mutations occur in this gene, they can either prevent the production of the MLH1 protein or alter its structure, impairing its ability to function effectively. This impairment leads to the accumulation of unrepaired DNA errors, which can result in uncontrolled cell proliferation and the formation of tumors. The most prevalent condition associated with MLH1 mutations is hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome. This condition significantly elevates the risk of various cancers, including those of the endometrium, ovaries, prostate, stomach, small intestine, liver, gallbladder duct, upper urinary tract, brain, and skin. The full sequence analysis performed under CPT® Code 81292 involves a comprehensive examination of the MLH1 gene to identify specific mutations, including point mutations or single nucleotide polymorphisms, which are the most common types of alterations found in this gene. Additionally, when a mutation is identified in an individual, it is recommended that family members undergo genetic testing to assess the presence of familial variants, thereby aiding in the evaluation of cancer risk among relatives.