Renin-angiotensin system gene polymorphisms and diastolic heart failure

Background: Diastolic heart failure (DHF) refers to an abnormality of diastolic distensibility, filling or relaxation of the left ventricle. The genetic study of DHF is scarce in the literature. The association of renin-angiotensin system (RAS) and DHF are well known. We hypothesized that RAS genes might be the susceptible genes for DHF and conducted a case-control study to prove the hypothesis. Materials and methods: A total of 1452 consecutive patients were analysed and 148 patients with a diagnosis of DHF confirmed by echocardiography were recruited. We had two control populations. The first controls consisted of 286 normal subjects while the second were 148 matched controls selected on a 1-to-1 basis by age, sex, hypertension, diabetes and medication use. The angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism; multilocus polymorphisms of the angiotensinogen gene; and the A1166C polymorphisms of the angiotensin II type I receptor (AT1R) gene were genotyped. Results: In a single-locus analysis, the odds ratios (ORs) for DHF were significant with the ACE DD genotype and the AT1R 1166 CC plus AC genotype. In addition, the concomitant presence of ACE DD and AT 1R 1166 CC/AC genotypes synergistically increased the predisposition to DHF. Conclusions: Genetic variants in the RAS genes may determine an individual's risk to develop DHF. There is also a synergistic gene-gene interaction between the RAS genes in the development of DHF.