Background: Hydrogen sulfide (H(2)S) plays an important role in the smooth muscle cell relaxation and thereby participates in the development of hypertension. Cystathionine gamma-lyase is the key enzyme in the endogenous production of H(2)S. Up to now, the reports on the relationship between the polymorphisms of cystathionine gamma-lyase gene (CTH) and essential hypertension (EH) are limited. This study was designed to assess their underlying relationship.
Methods: A total of 503 hypertensive patients and 490 age-, gender- and area-matched normotensive controls were enrolled in this study. Based on the FASTSNP, a web server to identify putative functional single nucleotide polymorphisms (SNPs) of genes, we selected two SNPs, rs482843 and rs1021737, in the CTH gene for genotyping. Genotyping was performed by the polymerase chain reaction and restriction fragment length polymorphism method (PCR-RFLP). The frequencies of the alleles and genotypes between cases and controls were compared by the chi-square test. The program Haplo. stats was used to investigate the relationship between the haplotypes and EH.
Results: These two SNPs were in Hardy-Weinberg Equilibrium in both cases and controls. The genotype distribution and allele frequencies of them did not significantly differ between cases and controls (all P > 0.05). In the stepwise logistic regression analysis we failed to observe their association with hypertension. In addition, none of the four estimated haplotypes or diplotypes significantly increased or decreased the risk of hypertension before or after adjustment for several known risk factors.
Conclusions: The present study suggests that the SNPs rs482843 and rs1021737 of the CTH gene were not associated with essential hypertension in the Northern Chinese Han population. However, replications in other populations and further functional studies are still necessary to clarify the role of the CTH gene in the pathogenesis of EH.