G-Protein b3 Subunit Gene Variant and Left Ventricular Hypertrophy in Essential Hypertension

A functional genetic variant consisting of a C825T substitution in the GNB3 gene, encoding for the G-protein b3 subunit, has been associated with enhanced G-protein activation and cell growth. The aim of the study was to investigate the association of this polymorphism with left ventricular hypertrophy (LVH) in a sample of patients with essential hypertension. Left ventricular mass was assessed by 2-mode echocardiography in 86 patients with essential hypertension, and GNB3 C825T genotype was determined by polymerase chain reaction and restriction digestion. Thirty-seven (0.43) patients were homozygous for the C allele (CC), 40 (0.47) were heterozygous (CT), and 9 (0.10) were homozygous for the T allele (TT). The genotype distribution among the patients was in Hardy-Weinberg equilibrium. Values of left ventricular end-diastolic diameter (52.060.7 versus 48.960.9 mm, P50.007), posterior wall thickness (11.360.2 versus 10.660.2 mm, P50.042), and left ventricular mass index (152.764.4 versus 135.266.4 g/m, P50.023) were significantly higher in patients with CT and TT genotypes considered together (CT1TT) than in CC patients. The distribution of the genotypes was significantly different when comparing patients with LVH: 20 (0.33) CC and 40 (0.67) CT1TT patients had this complication, and 17 (0.65) CC and 9 (0.35) CT1TT patients did not (P,0.01). The frequency of the T allele was significantly different among patients with (0.40) and without (0.20) LVH (P,0.01). A logistic regression analysis showed that the association between the T allele and LVH was independent of age, mean blood pressure, body mass index, and alcohol consumption. The relative risk of LVH in patients bearing the T allele (CT1TT group) compared with CC hypertensive patients was 3.03 (95% CI 1.14 to 8.05). The findings suggest an association between LVH and the 825T allele in hypertensive patients. (Hypertension. 2000;35[part 2]:214-218.)