A SUBTYPE OF DIABETES-MELLITUS ASSOCIATED WITH A MUTATION IN THE MITOCHONDRIAL GENE

Recently, in patients with diabetes and deafness, researchers have ide ntified an A to G transition at position 3243 in transfer ribonucleic acid(Leu(UUR)) [3243 base-pair (bp) mutation], originally found in pat ients with mitochondrial myopathy, encephalopathy, lactic acidosis, an d strokelike episodes. To determine the prevalence of diabetic patient s with this mutation in Japan, we screened selected cohorts of diabeti c patients based upon type of diabetes, family history of diabetes, an d age of onset; also screened were 550 unselected cohorts of diabetic patients, without prior information. We identified 5 patients with the 3243-bp mutation, suggesting that approximately 0.9% of diabetic pati ents have it. However, there were none with this mutation in 250 contr ols with normal glucose tolerance. We also studied the clinical charac teristics and insulin secretory characteristics of diabetic patients w ith 3243-bp mutation. We propose that diabetes mellitus with 3243-bp m utation is a novel subtype of diabetes mellitus, maternally inherited diabetes, and deafness (MIDD). (C) 1995 John Wiley and Sons, Inc.