FAMILIAL ADENOMATOUS POLYPOSIS

Question 1

Inheritance

Answer 1

Autosomal dominant

Question 2

Mutation

Answer 2

Germline mutation in adenomatous polyposis coli (APC) gene on chromosome 5

Question 3

Prognosis (4)

Answer 3

• Hundereds to thousands of colorectal adenomas usually by age 20
• 100% lifetime risk of CRC without prophylactic colectomy, onset in young adults
• Increased risk of extra-colonic malignancies: carcinoma of large bowel, bile duct, pancreas, stomach, thyroid, adrenal, and small bowel
• Congenital hypertrophy of retinal pigment epithelium

Question 4

FAP variants (3)

Answer 4

• Turcot’s syndrome: Multiple adenomatous colonic polyps with central nervous system (CNS) tumors (especially gliomas)
• Gardner’s syndrome: Innumerable polyps with associated osteomas, epidermal cysts, and bromatosis; colon cancer inevitable without surgery
• Attenuated FAP (fewer polyps at a later age)

Question 5

Screening

Answer 5

Start screening with colonoscopy at age 12 every year