Aldosterone synthase gene (CYP11B2) C-344T polymorphism in Caucasians fromthe Berlin Salt-Sensitivity Trial (BeSST)

Objective Aldosterone synthase (CYP11B2) is a key enzyme in the biosynthesi s of aldosterone. Recently, the T allele of a polymorphism in the 5'-fankin g region of the CYP11B2 gene (C-344T) has been reported to be more frequent in hypertensives than in normotensives, and has also been associated with increased plasma aldosterone levels. We therefore hypothesized that this va riant may be related to increased blood-pressure response to dietary salt i ntake. Subjects and methods We genotyped 163 young normotensive men recruited with in the framework of the Berlin Salt-Sensitivity Trial (BeSST) for the CYP11 B2 C-344T polymorphism. Subjects were characterized for family history of h ypertension, plasma parameters of the renin-angiotensin-aldosterone system and blood-pressure response to a high (220 mmol/day) and low (20 mmol/day) salt diet Results The frequency of the -344T allele (0.45) was similar to that report ed previously and genotype distribution was in Hardy-Weinberg equilibrium ( CC, n = 55; CT, n = 71; TT, n = 37). There was a trend towards a higher fre quency of the T allele in subjects with a positive family history of hypert ension (0.48 versus 0.42), but the C-344T genotype was not related to blood pressure under either diet Furthermore, when subjects were classified into salt-sensitive and salt-resistant groups, allelic distribution did not dif fer between the two groups (qT = 0.43 versus qT = 0.45). While renin activi ty and plasma aldosterone levels were not related to genotype, plasma angio tensinogen was significantly higher in T-allele carriers under both the hig h (P = 0.02) and low (P = 0.008) salt diet Conclusion Our findings do not support the hypothesis that the C-344T polym orphism of the CYP11B2 gene is associated with salt sensitivity or increase d activity of the renin-angiotensin system in young normotensive subjects. It is, therefore, unlikely that the C-344T polymorphism is a genetic marker for salt sensitivity in young normotensive Caucasian men. (C) Lippincott W illiams & Wilkins.