GS, like FAP, is genetically linked to a mutation in band 5q21, which is the adenomatous polyposis coli (APC) locus. It is relatively uncommon, affecting about one person per million. The average age at which patients are diagnosed with GS is 22. The most common cutaneous finding is epidermoid cysts (66%), which frequently predate the intestinal polyps, thus being one of the first signs of GS. If left untreated, the progression to malignancy is nearly 100%, which usually occurs between 30 and 50 years of age.
Other than intestinal cancer, other cancers are more common in patients with GS when compared with the general population, including duodenal, thyroid, and pancreatic carcinomas.
For more information on familial adenomatous polyposis, see OMIM.
D12.6 – Benign neoplasm of colon, unspecified
60876000 – Gardner Syndrome
- Ordinary epidermoid cysts – Present at a later age (post-puberty); they do not usually affect the face, scalp, or extremities as cysts associated with GS do. Are usually singular, not multiple as seen in with GS.
- Familial adenomatous polyposis (FAP) – Characterized by early development of thousands of large intestine tubular adenomas, often detected by age 35. A common initial sign of FAP is congenital hypertrophy of the retinal pigment epithelium. Epidermoid cysts may also be seen.
- Turcot syndrome – Characterized by up to 100 intestinal polyps, along with tumors in the brain. Skin manifestations include café-au-lait spots and basal cell carcinomas.
- Attenuated familial adenomatous polyposis – A form of FAP in which polyps develop and become malignant later in life.