Association of the −344C/T aldosterone synthase (CYP11B2) gene variant with hypertension and stroke

Abstract 

Stroke is a complex disease caused by combination of multiple risk factors. Recent findings have suggested that stroke has a significant genetic component. Various types of genetic polymorphisms have been suggested to contribute to the risk of stroke. Gene polymorphisms of renin-angiontensin aldosterone system (RAAS) have been suggested to be risk factors for hypertension, cardiovascular diseases and stroke. In the present case–control study we investigated the association of −344C/T (rs179998) polymorphism in the promoter region of the human aldosterone (CYP11B2) gene with genetic predisposition to hypertension, ischemic stroke and stroke subtypes classified according to TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification. Four hundred and three stroke patients (hypertensives:normotensives=219:184) and three hundred and ninety four, sex and age matched healthy controls (hypertensives:normotensives=118:276) were involved in the study. The region of interest in the CYP11B2 gene was amplified by polymerase chain reaction and genotypes determined by subjecting the PCR products to restriction digestion by the enzyme HaeIII. Significant difference was observed in the genotypic distribution and allelic frequency between the stroke patients and healthy controls. TT genotype and T allele associated significantly with hypertension and stroke (p<0.000 in hypertension and p=0.000 in case of stroke). A stepwise logistic regression analysis confirmed these findings. To establish that this polymorphism is associated with stroke independent of hypertension, we compared stroke patients without hypertension with normotensive controls. Significant difference was observed in genotypic distribution and allelic frequency between the two groups (p=0.000). Further evaluating the association of this polymorphism with stroke subtypes we found significant associations with intracranial large artery atherosclerosis, lacunar stroke and cardioembolic stroke (p=0.000 in each case). In conclusion our study suggests that −344T allele of CYP11B2 gene is an important risk factor for hypertension and ischemic stroke. However, this is a preliminary study and the results need to be confirmed in a larger cohort.

Keywords: Ischemic stroke, Aldosterone synthase gene, Hypertension, Intracranial large artery atherosclerosis, Lacunar stroke, Cardioembolic stroke