Association of G protein-coupled receptor kinase 4 gene polymorphism with salt sensitivity of blood pressure in a Gannan Tibetan population

Objective To investigate the association of G protein-coupled receptor kinase 4（GRK4） gene polymorphism with salt sensitivity of blood pressure in a Tibetan population of Gannan Tibetan Autonomous Prefecture. Methods From June 2013 to November 2014, a total of 787 Tibetans with essential hypertension and 660 Tibetans with normal blood pressure were enrolled using multistage random sampling method. The information was collected by questionnaires, physical examination and salt sensitivity test. The salt sensitivity was determined using the improved acute salt load test method in China. The DNA was extracted from 6 mL of peripheral venous blood and tested for the single nucleotide polymorphisms（SNP） of GRK4. According to blood pressure and salt sensitivity, the subjects were divided into four groups including salt-sensitive hypertension（n=554）, non-salt-sensitive hypertension（n=233）, salt-sensitive normotension（n=423） and non-salt-sensitive normotension（n=237）. The differences in characteristics and distribution of genotypes and alleles at each locus among four groups were analyzed. Logistic regression was used to analyze the relationship between GRK4 gene and the salt sensitivity of blood pressure in Tibetan population. Results The distribution of genotypes and allele frequencies in rs12506119 and rs1419043 were significantly different among four groups（all P＜0.05）. Non-salt-sensitive normotension was used as control, after adjusting for confounding factors age, gender, education, occupation, smoking, drinking, physical exercise and body mass index（BMI）, multivariate Logistic regression analysis showed that C allele mutation（CG+CC genotype） was a protective factor for salt-sensitive hypertension group compared with GG genotype at rs1419043（OR=0.06, 95% CI=0.01-0.93, P=0.04）. Conclusion GRK4 gene locus rs1419043 may be associated with the occurrence of salt-sensitive hypertension in the Tibetan population of Gannan.