gastrointestinal disorders
Familial Adenomatous Polyposis
Introduction
Familial adenomatous polyposis is a hereditary disorder causing numerous colonic polyps and frequently results in colon carcinoma, often by age 40. Patients are usually asymptomatic but may have heme-positive stool. Diagnosis is by endoscopy and genetic testing. Treatment is colectomy. Familial adenomatous polyposis is an autosomal dominant disease in which≥100 adenomatous polyps carpet the colon and rectum. The disorder occurs in 1 in 8,000 to 14,000 people. Polyps are present in 50% of patients by age 15 years, and 95% by age 35 years. Cancer develops before age 40 in nearly all untreated patients. Patients also can develop various extracolonic manifestations (previously termed Gardner syndrome), both benign and malignant. Benign manifestations include desmoid tumors, osteomas of the skull or mandible, sebaceous cysts, and adenomas in other parts of the gastrointestinal tract. Patients are at increased risk of cancer in the duodenum (5 to 11%), pancreas (2%), thyroid (2%), brain ( Medulloblastoma in 