Correlation between left ventricular mass and urinary sodium excretion in specific genotypes of CYP11B2.
BACKGROUND
Aldosterone has essential roles in regulating intravascular volume and blood pressure, and is suggested to influence cardiac structure. However, the association of polymorphisms in the aldosterone synthase gene (CYP11B2) with hypertension or cardiac hypertrophy remains controversial.


OBJECTIVE
To evaluate the distribution of polymorphisms in the CYP11B2 gene and the possible associations between genotypes and blood pressure, urinary excretion of aldosterone or electrolytes and echocardiographic measurements, in a Japanese population.


RESULTS
We examined the association of two common diallelic polymorphisms within CYP11B2, one in the promoter -344T/C and the other an intron 2 gene conversion, with blood pressure, 24-h urinary excretion of aldosterone and electrolytes, and echocardiographic measurements, in a Japanese population. We confirmed significant linkage disequilibrium between these polymorphic loci and ethnic differences in frequency of the alleles. The -344C and -344T haplotypes apparently diverged before the intron conversion polymorphism was generated on the latter haplotype. Allele frequencies did not differ between 535 normotensive and 360 hypertensive individuals or between hypertensive individuals with higher and lower concentrations of renin. The only significant correlation was a positive correlation of left ventricular mass with 24-h urinary excretion of sodium, which occurred only in individuals with the -344CC genotype or the intron 2 conversion (-/-) genotype.


CONCLUSIONS
The -344CC or intron 2 conversion (-/-) genotype in CYP11B2 may be a risk factor for developing sodium-sensitive cardiac hypertrophy. Ethnic differences in the distribution of CYP11B2 genotypes combined with differences in salt intake might account for inconsistencies between previous reports.
Isaji
Mako
M
Department of Diabetes and Endocrinology, Gifu University School of Medicine, Yanagido, Gifu, Japan.
Mune
Tomoatsu
T
Takada
Nobuki
N
Yamamoto
Yoritsuna
Y
Suwa
Tetsuya
T
Morita
Hiroyuki
H
Takeda
Jun
J
White
Perrin C
PC
D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics*; D004452:Echocardiography; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D005838:Genotype; D006801:Humans; D006977:Hypertension, Renal / Q000453:epidemiology* / Q000235:genetics* / Q000652:urine; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000235:genetics* / Q000652:urine; D008297:Male; D008875:Middle Aged; D012083:Renin / Q000097:blood; D012307:Risk Factors; D012964:Sodium / Q000652:urine*
D012964:Sodium; D019405:Cytochrome P-450 CYP11B2; D012083:Renin