Background: Nuclear genome or family mitochondrial screening system has become the hot focus of studies into essential hypertension. The role of mitochondrial DNA (mtDNA) in sporadic Chinese patients with hypertension has not been fully understood. The study was to evaluate the associations of mtDNA mutations with maternally inherited essential hypertensive (MIEH) subjects in China.
Methods: From June 2009 to June 2016, a total of 800 gender-matched Chinese patients with maternally inherited essential hypertension (MIEH) and control group were 1:1 enrolled in this case-control study. Genomic DNA was extracted from each person's peripheral blood cells. The main mtDNA locations for MIEH were screened with oligodeoxynucleotides 3777-4679bp, analyzed and compared with the updated consensus Cambridge Sequence. Pathogenic mtDNA mutations were identified from the mitochondrial map.
Results: MIEH subjects presented significantly higher values than those of control group in abdominal circumference(AC), waist circumference(WC), body mass index(BMI), fasting blood glucose(FBG), triglyceride(TG), low-density lipoprotein cholesterol (LDL) and renal function ( P <0.05). MIEH subjects carried more amino acid changes and coding sequence variants ( P <0.01) than control group. The allele frequencies of the eight single nucleotide polymorphisms(SNPs) were significantly different between the two groups, including C3970T, G4048A, C4071T, C4086T, A4164G and T4248C in ND1 gene, and T4386C and C4394T in tRNA Gln gene( P <0.001). Fifty-five homoplasmic or heteroplasmic mutations were detected in 5 genes: ND1, tRNA Ile , tRNA Met , tRNA Gln and ND2 gene. The ND1 gene was the main mutation site, where the most mtDNA mutation was C3970T.
Conclusions: The results convincingly proved that mtDNA mutations were involved in the process of MIEH. We identified mitochondrial genetic characteristics in MIEH patients in China. The present research serves as a solid foundation for further detailed research on the association between MIEH and mitochondrial dysfunction, and their causal relationship in Chinese and other populations with a similar lifestyle.