Hyperproinsulinemia in Japan.

Abstract Four families with hyperproinsulinemia found in Japan were described. The details of the first case, who was investigated by Kanazawa et al, were reported and the similarity of the first case to the following cases was shown. Arginine 65 of the proinsulin molecule might be a hot spot of the insulin gene. A possible abnormality of insulin release in affected individuals was disclosed by investigation of the family members of the first case.