To analyze the clinical characteristics and gene mutation results in a family with diabetes, in order to improve the knowledge of the diabetes caused by mitochondrial gene mutation.

Genomic DNA was extracted using standard procedure from peripheral blood of the family members, and targeted next generation sequencing was performed on the proband to capture and sequence the entire mtDNA and nuclear genes related to mitochondrial structure and function.Moreover, other patients and members from the family were performed directed sanger sequence to detect the genetic information of the mitochondrial genes.Meanwhile clinical data were collected and analyzed.

mtDNA 3243A>G mutation was detected in 3 of 8 members in the family.Among these 3 members, 2 cases were diagnosed diabetes by the onset before the age of 40, with low body mass index (BMI), negative autoimmune diabetes antibody and accompanied by nerve deafness.In addition, another member aged 10 was detected mtDNA 3243A>G mutation without clinical diabetes characteristics until now.

mtDNA 3243A>G mutation is the cause of the diabetes of this family, and the clinical manifestation of the patients with early onset, low body weight and nerve deafness conforms to the mitochondrial diabetes.