The 894T allele of endothelial nitric oxide synthase gene is related to left ventricular mass in African Americans with high-normal blood pressure.
OBJECTIVE
The 894T allele in exon 7 of the endothelial nitric oxide synthase (eNOS) gene has been inconsistently associated with hypertension in different racial groups. Because high-normal blood pressure (BP) confers an increased risk for the development of hypertension and other cardiovascular disorders, including left ventricular hypertrophy (LVH), we tested the hypothesis that the allelic variation (894T) in the eNOS gene would directly correlate with alterations in LV mass (LVM) in individuals with high-normal BP.


METHODS
Genotype distribution of G894T was compared between 20 African Americans (10 females/10 males) with high-normal BP (systolic BP of 130-139 and/or diastolic BP of 85-89 mmHg) and 64 counterparts (37 females/27 males) with normal BP (<130/85 mmHg). Echocardiographic LVM was calculated (Devereux formula) and indexed to body surface area to define the presence of LVH (LVMI >134/110 g/m2 for men/women).


RESULTS
For the entire group, the 894T allelic frequencies (15, 48%) and G894T genotype distributions were consistent with the Hardy-Weinberg equilibrium expectations (estimated disequilibrium coefficient = 0.0118, P=0.40). LVMI was significantly higher in homozygous carriers (TT) of the rare 894T allele (n = 3 females/0 males) than in heterozygous GT (n = 13 females/7 males) and individuals bearing the GG (n=34 females/27 males) variant (124 +/- 70 vs. 82 +/- 24 and 82 +/- 19 g/m2, respectively, P < 0.05). The observed relationship between eNOS 894T allele and LVMI was restricted to individuals with high-normal BP (r = 0.94, P = 0.03) but not in those with normal BP (r = 0.39, P =0.64), by analysis of variance (ANOVA) after adjusting for age, gender, body mass index, smoking and systolic BP.


CONCLUSIONS
These findings, not previously described, provide important preliminary evidence to suggest an increased susceptibility to LVH in African Americans who carry the 894T variant of the eNOS gene and have high-normal blood pressure.
Lapu-Bula
Rigobert
R
Division of Cardiology, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310, USA. lapbulr@msm.edu
Quarshie
Alexander
A
Lyn
Deborah
D
Oduwole
Adefisayo
A
Pack
Cheryl
C
Morgan
Jan
J
Nkemdiche
Sunday
S
Igho-Pemu
Priscilla
P
Onwuanyi
Anekwe
A
Li
Rongling
R
Ofili
Elizabeth
E
D000328:Adult; D001741:Black or African American / Q000235:genetics*; D000483:Alleles; D001794:Blood Pressure; D003326:Coronary Circulation / Q000235:genetics; D004730:Endothelium, Vascular; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D006973:Hypertension / Q000208:ethnology* / Q000235:genetics*; D017379:Hypertrophy, Left Ventricular / Q000208:ethnology* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052250:Nitric Oxide Synthase Type III; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors
C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III