Gene polymorphisms of the renin-angiotensin system in essential hypertension

Objective To determine whether angiotensin-converting enzyme (ACE) gene, angiotensinogen (AGT) gene and angiotensin IE receptor 1 (AT1R) gene are implicated in Chinese essential hypertension (EH). Methods The case-control and haplotype-based haplotype relative risk (HHRR) study consisted of 169 essential hypertensive subjects ( HT), 152 normotensive controls (NT) and 62 families. The polymorphisms of insertion/deletion (I/D) allele of ACE gene and the microsatellite allele of AT1R gene were determined in DNA extracted from peripheral blood leukocytes by polymerase chain reaction (PCR). The variants of AGT gene were screened by PCR-single strand conformation polymorphism (PCR-SSCP) analysis and further identified by cloning and sequencing. Results The significant association between EH and D allele of ACE gene was found (P < 0. 05). The difference of the microsatellite allele distribution of AT1R gene between HT and NT groups was statistically significant (P < 0.005). By contrast, the distribution of A-20C genotype of AGT gene was almost identical in HT and NT groups. No significant linkage disequilibrium was observed between A-20C and M235T in AGT gene. Conclusions D allele of ACE gene might correlate with a predisposing factor for EH. The microsatellite allele of AT1R gene might be linkage disequilibrium with an unidentified variant that contributes to the development of EH. A-20C of AGT gene is not a major genetic determinant of EH.