Abstract
Because of the low incidence of type 1 diabetes in the general population, familial clustering of this type of diabetes is rare among Japanese. We encountered a clustering of it in a mother and daughter, and the clinical characteristics of the cases are herein reported. Case 1 (mother) was a 49-year-old woman who had been diagnosed as having diabetes at the age of 39 because of grossly elevated random sample plasma glucose level, 360 mg/dl. After an initial treatment at that time, near-normal glycemia was maintained without drug therapy for 8 months. However, insulin injection had to be resumed for glycemic control thereafter and she is currently on intensive insulin therapy. Insulin secretion was well measurable at the onset, but it gradually deteriorated, and has been totally absent for the past 5 years. Anti-GAD antibody, measured 10 years after the onset, was 2U/ml. The daughter (Case 2) was 17-year-old and found to be diabetic (fasting plasma glucose, 313 mg/dl) during a preoperative examination for ovarian tumor. Insulin therapy was instituted and continued thereafter. Insulin secretion is maintained in this case. Anti-GAD antibody was 68.7U/ml 3 months after the onset. A younger sister is currently normoglycemic with normal insulin response at 75 g OGIT. All three of these patients were homozygotes for DR 9-DQA 1*03-DQB 1*0303, a high-risk haplotype for the development of type 1 diabetes.
