Gene polymorphisms of the renin-angiotensin system in essential hypertension

Objective To determine whether angiotensin-converting enzyme (ACE) gene, an giotensinogen (AGT) gene and angiotensin IE receptor 1 (AT1R) gene are impl icated 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 normoten sive controls (NT) and 62 families. The polymorphisms of insertion/deletion (I/D) allele of ACE gene and the microsatellite allele of AT1R gene were d etermined in DNA extracted from peripheral blood leukocytes by polymerase c hain reaction (PCR). The variants of AGT gene were screened by PCR-single s trand 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 distributio n 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 alm ost identical in HT and NT groups. No significant linkage disequilibrium wa s 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 disequilib rium with an unidentified variant that contributes to the development of EH . A-20C of AGT gene is not a major genetic determinant of EH.