Nine different germline mutations in the coding, as well as in the 5′-UTR of the CDKN1B gene have been described in patients with familial or sporadic MEN1-like syndromes, but negative for MEN1 mutations (7, 8, 9, 10, 11, 12, 13). The gene discussed is MEN1; the disease is multiple endocrine neoplasia type 1.