THE HIGH PREVALENCE OF THE DIABETIC-PATIENTS WITH A MUTATION IN THE MITOCHONDRIAL GENE IN JAPAN

Recently, an A to G transition at position 3243 in transfer ribonuclei c acid(Leu(UUR)) [the 3243 base-pair (bp) mutation] originally found i n patients with mitochondrial myopathy, encephalopathy, lactic acidosi s, and stroke-like episodes has been identified in patients with diabe tes and deafness. To determine the prevalence of the diabetic patients with this mutation in Japan, we screened 550 randomly selected cohort s of diabetic patients without prior information about clinical featur es such as type of diabetes, family history of diabetes, age of onset, and mode of therapy. We have identified 5 patients with this mutation , suggesting that approximately 0.9% of diabetic patients have the 324 3 bp mutation. However, there were no subjects with this mutation in 2 50 controls with normal glucose tolerance. The percentage of mutant DN A in whole mitochondrial DNA did not correlate to the degree of sympto ms. We conclude that the 3243 bp mutation in the mitochondrial gene pl ays an important part as a cause of diabetes in Japan.