[MtDNA haplogroup U4b is a genetic susceptibility factor for high altitude essential hypertension in the Chinese Tajik population].

To investigate the relationship between mitochondrial DNA (mtDNA) variation and high altitude essential hypertension(HAEH) in the Chinese Tajik population. Fifty-three patients with HAEH and 46 healthy subjects were enrolled from the Chinese Tajik population. The mtDNA fragments were amplificated by polymerase chain reaction, and products were sequenced to acquire full sequence of mtDNA. The mtDNA sequences of all subjects were compared to the Cambridge sequence to explore mtDNA variations and analyze difference between HAEH and healthy controls. Online softwares were applied to predict function changes caused by positive associated mtDNA variations. Compared to the control group, the frequency of haplogroup U4b was significant higher in HAEH group(=0.023,OR=7.062,CI(95%)=1.306-38.182), and the frequencies of 8 mutations from haplogroup U4b showed a significant difference between the HAEH group and control group (all with values below 0.05). The mt DNA15693T＞C mutation was the only missense mutation, which affected amino acid 316 in mitochondrial cytochrome b (MTCYB) by changing it from methionine to threonine. Bioinformatics analysis indicated that the mutation in MTCYB may play a biological role through affecting the second structure of protein. MtDNA subhaplogroup U4b is a genetic factor for HAEH in the Chinese Tajik population, and mtDNA15693T＞C mutation may be an important molecular mechanism of HAEH.