CDKN1B and multiple endocrine neoplasia type 1: Familial CD has been reported in germline mutations of the tumor suppressorMENIN (causing multiple endocrine neoplasia type 1 syndrome, or MEN1), aryl-hydrocarbon receptor-interacting protein gene (AIP), andCDKN1B gene (orp27/Kip1) that encodes for p27, a cell cycle inhibitor and causes multiple endocrine neoplasia type 4 (MEN4)35–41.