CPT® Code 81203

APC (adenomatous polyposis coli) (eg, familial adenomatosis polyposis [FAP], attenuated FAP) gene analysis; duplication/deletion variants

The CPT® Code 81203 pertains to the molecular genetic testing specifically aimed at identifying duplication and deletion variants of the adenomatous polyposis coli (APC) gene. This gene is crucial in the context of familial adenomatosis polyposis (FAP), a hereditary condition characterized by the development of numerous polyps in the colon and rectum, which can lead to colorectal cancer if left untreated. FAP is inherited in an autosomal dominant manner, meaning that an individual only needs to inherit the mutated gene from one parent to be affected by the condition. The classic form of FAP is typically more severe than its attenuated counterpart, which presents with fewer polyps and a later onset of symptoms. The APC gene plays a vital role as a tumor suppressor, and mutations in this gene disrupt its function, leading to uncontrolled cell growth and polyp formation. The gene is located on chromosome 5, and over 700 distinct mutations have been documented, many of which result in a truncated, nonfunctional APC protein. The testing associated with CPT® Code 81203 is essential for detecting specific genetic alterations that may predispose individuals to colorectal cancer, thereby facilitating early intervention and management strategies. This code is specifically used for testing that identifies duplication or deletion variants, which are critical for understanding the genetic basis of the disease and for guiding patient care.