Objective: Essential hypertension (EH) was a complex disease resulted from the interaction of cumulative effect of multiple genetic and environment factors. The relationship between the genetic polymorphisms in the transforming growth factor-beta1 (TGF-beta1), the blood levels and EH have been investigated, but the conclusions were different. Therefore, we investigate the relationship between the tagging single nucleotide polymorphisms (tSNPs) (rs1800469, rs2241716, rs11466345, rs2241715, rs4803455) in TGF-beta1 gene, blood levels and EH in the Han nationality population in Xinjiang, to clarity the pattern of linkage disequilibrium (LD) and the feature of the structure of haplotype.
Methods: Based on the case-control study,we selected 732 (365 EH patients,367 controls) Han Chinese population from the Boertonggu countryside of Shawan region in the Xinjiang Uygur Autonomous Region of China by random cluster sampling. After questionnaire and physical examination, we collected blood samples, and the blood levels of TGF-beta1 were quantified using sandwich ELISA. The polymorphisms of TGF-beta1 gene in the study groups were detected with SNaPshot system. The case-control study in a large group was carried out separately for each of the tSNP and followed up by haplotypes analyses to determine the relation between tSNPs of TGF-beta1 gene and EH in the Han population.
Results: (1) The frequencies of alleles A, G of rs11466345 of TGF-beta1 gene in EH group and control group were as follows: 69.7%, 30.3%, 74.4%, 25.6%, respectively. It was demonstrated that the G allele of the rs11466345 polymorphism occurred at a significantly higher frequency in EH patients than in healthy controls (30.3% vs. 25.6%, P < 0.05). The rs11466345G-allele carriers had a significantly increased risk of EH compared to rs11466345A-allele carrier (OR = 1.261; P < 0.05). The frequencies of genotypes and alleles of the other tSNPs of TGF-beta1 gene had no difference between EH patients and controls (P > 0.05). (2)Except the site of rs11466345, the other tSNPs were in strong LD, and no statistical differences were observed in haplotypes distribution in the followup study between case-control groups (P > 0.05). (3) There were no difference of TGF-beta1 levels between the different genotypes and alleles in tSNPs of TGF-beta1 gene (P > 0.05).
Conclusions: (1) These results suggested that TGF-beta1 gene rs11466345 G allele was likely to be a genetic susceptibility factor for EH in the Xinjiang Han population, the other tSNPs perhaps had no association with EH of in the study groups. (2) Except rs11466345, the other tSNPs were in strong LD, and the haplotypes reconstructed by tSNPs might not be associated with EH in the Han nationality populations. (3) There was no association between the tSNP of TGF-beta1 gene and TGF-beta1 blood levels in the Xinjiang Han nationality population.