Randall W. Burt, MD

Approximately 6% of colorectal cancers can be attributed to recognizable heritable germline mutations. Familial adenomatous polyposis is an autosomal dominant syndrome classically presenting with hundreds to thousands of adenomatous colorectal polyps that are caused by mutations in the APC gene.

Over 130,000 new cases of colon cancer are diagnosed annually. Approximately 20% to 30% of these are attributable to familial risk, and 3% to 5% belong to a hereditary colorectal cancer predisposition syndrome.

Multiple endocrine neoplasia type 2 (MEN-2) may be the ideal diseasefor presymptomatic genetic testing. The syndrome has an autosomaldominant pattern of inheritance and includes medullary thyroidcarcinoma, pheochromocytomas, and, sometimes, parathyroid adenomas.The risk of medullary thyroid carcinoma in affected persons isextremely high.