Polymorphisms of the insulin gene among Japanese subjects

We have sequenced the insulin gene in 72 unrelated Japanese subjects (52 wi th type 2 diabetes mellitus and 20 with normal glucose tolerance). We ident ified 6 mutations and all were found at a low frequency (1% to 4%). Three m utations were new. These included a C-to-G substitution in the promoter reg ion, a G-to-A substitution in codon-2 resulting in an Ala-to-Thr replacemen t in amino acid -2 of the signal peptide, and a G-to-A substitution in intr on 2. We have no evidence that any of the mutations that we found are the c ause of diabetes. Thus, mutations in the insulin gene do not appear to be a n important genetic factor contributing to the development of diabetes in t his population. Copyright (C) 2001 by W.B. Saunders Company.