Age of onset is variable. The term<unk> ' in the title of<unk>  refers to the histological type of the polyps rather than the age of onset. Affected individuals may present with rectal bleeding, abdominal pain, diarrhea or anemia. On colonoscopy or sigmoidoscopy polyps that vary in shape or size are present. The polyps can be sessile or pedunculated hamartomatous polyps.
Juvenile polyposis syndrome
Familial adenomatous polyposis
Serrated polyposis syndrome
Hereditary diffuse gastric cancer
Hereditary nonpolyposis colorectal cancer
MUTYH-associated polyposis
Peutz–Jeghers syndrome
Ogden syndrome