Background: Abnormalities in renal sodium and water retention and membrane ion transport play important roles in development of hypertension. Recently, Arg904Gln variant of thiazide-sensitive NaCl-cotransporter gene (TSC) and Thr418Ser variant of renal epithelial Cl-channel ClC-Kb gene (CLCNKB) were found implicated in the prevalence of essential hypertension (EH). The objective of this study was to examine the role of these two variants on EH in two Chinese minorities -- Kazaks and Uyghurs.
Methods: A case-control study was conducted in Kazak herdsmen and Uyghur farmers live in Xinjiang Uyghur Autonomous Region of Northwest China.
Results: For the Arg904Gln polymorphism in the TSC gene, we observed a stronger trend of 904Gln allele in controls than hypertensives in Uyghurs (p=0.058), but the greater prevalence of genotype of 904Gln carrier reached significance (p=0.015). No association or trend with hypertension was observed at Arg904Gln in Kazaks. For the Thr418Ser variant of the CLCNKB gene in Kazaks, we observed a significantly higher prevalence of 418Ser allele frequencies in hypertensives than controls (p=0.037), but the higher prevalence of genotype of 418Ser carrier did not reach significance (p=0.08). No association with hypertension was observed at Thr418Ser in Uyghurs.
Conclusion: The risk reduction effect of 904Gln to hypertension in Uyghurs and the association of 418Ser to hypertension in Kazaks are weak. Given that we have explored two polymorphisms in each of two populations, for a total of four independent tests, a Bonferroni correction for multiple tests (0.05/4) renders non-significant of our results in our two Chinese populations (alpha=0.0125). The roles of Thr418Ser polymorphism of the CLCNKB gene and Arg904Gln polymorphism in the TSC gene on essential hypertension need to be explored in other ethnic groups.