CPT® Code 81294

MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) (eg, hereditary non-polyposis colorectal cancer, Lynch syndrome) gene analysis; duplication/deletion variants

The CPT® Code 81294 pertains to the molecular genetic testing of the MLH1 gene, specifically focusing on the analysis of duplication and deletion variants. The MLH1 gene, located on chromosome 3, plays a crucial role in the body's ability to repair DNA. Mutations in this gene can significantly increase an individual's risk of developing colorectal cancer and other associated cancers. This condition is often referred to as hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome, which is characterized by a higher likelihood of various cancers, including those of the endometrium, ovaries, prostate, stomach, small intestine, liver, gallbladder duct, upper urinary tract, brain, and skin. The testing process aims to identify specific mutations that may prevent the production of the MLH1 protein or alter its function, leading to the accumulation of unrepaired DNA errors. These errors can result in uncontrolled cell proliferation, ultimately leading to tumor formation. The analysis for deletion and duplication variants is essential, as a normal MLH1 gene should have two copies per cell, with deviations indicating potential genetic issues. A deletion variant is indicated by the presence of zero or one copy, while a duplication variant is suggested by three or more copies. Understanding these genetic variations is vital for assessing cancer risk in affected individuals and their family members, as it can guide further testing and preventive measures.