Mitochondrial tRNASer(UCN) 7471delC may be a novel mutation associated with maternally transmitted hypertension.

Abstract

The objective of the study was to investigate the association between mitochondrial DNA (mtDNA) mutations and essential hypertension (EH). One Han Chinese pedigree with maternally inherited EH was recruited in the current study. The matrilineal relatives from this family underwent clinical, genetic, and molecular analysis. Moreover, the mtDNA gene mutations were screened by PCR and direct Sanger sequence. Evolutionary conservation was performed and the secondary structure of mt-tRNASer(UCN) with and without the 7471delC was evaluated by the RNA Fold Webserver program. Moreover, the pathogenicity scoring system was used to assess the 7471delC. This Chinese pedigree exhibited a relative high penetrance and expressivity of EH. Of 13 matrilineal relatives, 5 of them suffered from high blood pressure (BP). Genetic analysis of the complete mtDNA genes showed the presence of a novel tRNASer(UCN) 7471delC, together with a set of polymorphisms belonging to the human mitochondrial haplogroup G2a1. In fact, the 7471delC occurred within the T-stem and extra arm of tRNASer(UCN), which was very conserved from bacteria to human mitochondria. Interestingly, the 7472insC which was located at the same position had been regarded as a pathogenic mutation associated with non-syndromic hearing loss. In addition, bioinformatics analysis revealed that the 7471delC affected the secondary structure of tRNASer(UCN). The pathogenicity scoring system showed that the 7471delC may be "possibly pathogenic" associated with EH. We believed that the 7471delC may impair the mitochondrial functional and played an active role in the pathogenesis of EH in this pedigree. The 7471delC may be a novel risk factor for maternally transmitted EH.