GardnerSyndrom

Gardner syndrome is a phenotypic variant of familial adenomatous polyposis (FAP) characterized by colorectal polyposis along with distinctive extracolonic manifestations, including osteomas of the skull and mandible, dental anomalies such as supernumerary teeth and odontomas, epidermoid cysts, and desmoid tumors. Additional soft-tissue tumors and CHRPE retinal lesions may be observed. The condition is caused by germline mutations in the APC gene on chromosome 5q21-22 and is inherited in an autosomal dominant pattern with high penetrance but variable expressivity.

Clinically, individuals develop hundreds to thousands of colonic polyps during adolescence or early adulthood, with a near certainty of colorectal cancer if untreated. Extracolonic features often precede or accompany colorectal disease and aid in recognition. Dental abnormalities and jaw osteomas can be early clues.

Diagnosis relies on clinical assessment, endoscopic detection of polyposis, imaging for osteomas, and genetic testing confirming an APC pathogenic variant. Family history supports the diagnosis.

Management requires a multidisciplinary approach. Surveillance includes regular colonoscopic polyp monitoring, upper GI endoscopy where indicated, dental evaluation, and imaging for desmoid tumors. Prophylactic colectomy is often considered when polyp burden is high or cancer risk is substantial. Desmoid tumors and other extracolonic manifestations may require surgical, medical, or radiation therapy, with NSAIDs or anti-estrogen therapies used in some cases.

Genetic counseling is essential due to autosomal dominant transmission and implications for at-risk relatives.

Prognosis depends on cancer risk and the behavior of desmoid tumors; early recognition improves outcomes.