Mitochondrial Gene Mutations in the tRNALeu(UUR) Region and Diabetes: Prevalence and Clinical Phenotypes in Japan

in the development of diabetes mellitus. We have as-sessed the frequency of the A3243G and other mitochon-drial mutations in Japan and in the relationship to clinical features of diabetes. Methods: DNA was obtained from peripheral leuko-cytes of 240 patients with diabetes mellitus (39 with type 1; 188 with type 2; 13 with gestational diabetes) and 125 control subjects. We used PCR-restriction fragment length polymorphism analysis (ApaI) for A3243G and PCR-single-strand conformation polymorphism analy-sis to determine the mutations in the mitochondrial gene including nucleotide position 3243. Results: The A3243G mutation was found in seven patients, and an inverse relationship was observed be-tween the degree of heteroplasmy and the age at onset o