85 家族性大腸息肉症（Familial adenomatous polyposis）與下列何種基因變異關係最密切？
(A) APC/β-catenin
(B) RB gene
(C) p53 gene
(D) TGF-β receptor

Familial polyposis – need to have over 100 polyps to have familial polyposis.   This dz is autosomal dominant, uses APC suppressor gene, ras, and p53; APC is the major one.   Will always get cancer in them, usually between 35-40.  Therefore, will need to prophylactically remove the bowel.  The autosomal dominant dz is famous for late manifestations, penetrance, and variable expressivity (as are all other AD dz’s).  This means that they will not be born with polyps at birth (they start developing btwn the ages of 10-20; in ADPKD, they do   not have cysts are birth, they start developing btwn 10-20; in Huntington’s chorea, do not have chorea at birth, but around 35-40 years, and they have late manifestations.