[Study on a new point mutation of nt7444 G-->A in the mitochondrial DNA in a type 2 diabetes mellitus family].

Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and direct sequencing were applied to detect a new point mutation of nt7444G-->A in the mitochondrial DNA in a type 2 diabetes mellitus family. The related clinical data were also collected and analyzed. mtDNA G7444A mutation in the cytochrome c oxidase I (COI) gene was found in 11 of 27 cases, all of whom were from the maternal side. Among them, 5 were confirmed to have type 2 diabetes mellitus, and one had impaired glucose tolerance. We conclude that the novel point mutation of mtDNA G7444A may be an independent factor associated with type 2 diabetes mellitus.