Association Between MtDNA3243, 3316 Mutations And Patients With Type 2 Diabetes Mellitus In Yunnan Chinese

Objective: To investigate the prevalence of the must prevalent mitochondrial DNA mutation at position 3243(A / G) and the prevalence of the mitochondrial DNA mutation at position 3316(G / A) in Chinese patients with type 2 diabetes mellitus and to establish the approaches for genetic diagnosis of this subtype of diabetes during routine daily clinical practice. Subjects and Methods: We randomly examined 225 unrelated Chinese patients with type 2 diabetes and 195 nondiabetic control individuals without family history of diabetes. The presence of mt 3243 and 3316 mutations was determined by polymerase chain reaction amplification and restriction fragment length polymorphism (PCR/RFLP). Finally, mutant mtDNA was confirmed by DNA sequencing. Results: The mitochondrial DNA mutation at position 3243 was not found in any of the patients and controls. The mitochondrial DNA mutation at position 3316 was found in 5 of 225 ( 2.22 %) patients with type 2 diabetes, and this mutation was found in 2 of 195 ( 1.03 %) control individuals. Therefore the frequency of the mutation was not different between patients and controls. Above results were identified by DNA sequencing. Conclusions: Our results suggest that the prevalence of the mitochondrial tRNALeu(UUR) gene at position 3243 (A / G) mutation was exactly very lowand it may not a major cause of type 2 diabetic patients in China. The mitochondrial ND-1 gene at position 3316(G/A) mutation may be a polymorphism unrelated to diabetes in China. The role of other genetic, environmental and intrauterine factors needs further investigation.