Analysis of candidate genes and hypertension in African American adults

Objective: We investigated the associations between hypertension status and the genotypes of four single nucleotide polymorphism (SNP) sites in four hypertension-related genes (Angiotensinogen [AGT], Angiotensin I Converting Enzyme [ACE], Angiotensinogen II receptor, subtype 1 [AGTR1], and Alpha 1-Antichymotrypsin [ACT or SERPINA3]), in an African American sample. Methods: DNA from 628 participants of the Carolina African American Twin Study of Aging project, a population-based study of African American adult twins, was genotyped using SNPs shown to be associated with hypertension in other studies. Results: The ACE SNP (ACE4 or A-240T) was associated with hypertension (P5.047 in a generalized estimating equations alternating logistics regression model that included age, body mass index, sex, and education. The analysis indicated a protective effect of the TT genotype (odds ratio [OR] 1.59, 95% confidence interval [CI] 1.03-2.48, P=.04) and of the AT genotype (OR 1.91, 95% CI 1.01-3.62, P=.047) compared with the AA genotype. Discussion: These results extend previous findings of associations of various polymorphisms of ACE to hypertension and support the association of hypertension to the A allele of ACE4. The potential for this polymorphism to alter expression by its position in the gene's promoter region suggests that future studies of altered ACE protein activity are warranted.