G-Protein beta3 subunit C825T variant and ambulatory blood pressure in essential hypertension

Recent studies have identified a novel polymorphism (C825T) of the gene encoding the beta3 subunit of heterotrimeric G proteins (Gbeta3) associated with enhanced activation of G proteins, which appears to be more common in hypertensive patients. In the present study we examine the relationship between this genetic variant and hypertension in 479 white patients with established essential hypertension recruited from the hypertension clinic of the Universitätsklinikum Benjamin Franklin in Berlin, Germany, and 1000 normotensive gender- and age-matched controls. All patients were screened for the presence of secondary hypertension and were further characterized by ambulatory blood pressure measurements performed in 295 treated and 184 untreated patients. Genotype distribution for the Gbeta3-C825T genotype in patients (CC=204, CT=224, TT=51) was significantly different from that in controls (CC=514, CT=412, TT=74; chi2=11.5, P<0.01), and the T allele was associated with an odds ratio of 1.5 (95% CI, 1.1 to 2.2) versus non-T carriers for the presence of hypertension. However, in both the whole group and the untreated subgroup, blood pressure levels between the genotypic groups were virtually identical. Furthermore, age of onset of hypertension and number of antihypertensive medications (in treated patients) were similar between the genotypic groups. Thus, while our data confirm the association between the Gbeta3-C825T variant and essential hypertension, they do not support the hypothesis that this marker is associated with more severe blood pressure in patients with already established hypertension.