A Functional Variant of NEDD4L Is Associated With Hypertension, Antihypertensive Response, and Orthostatic Hypotension

NEDD4L is involved in the regulation of plasma volume and blood pressure by controlling cell surface expression of the kidney epithelial Na+ channel. Previously, the cryptic splice variant rs4149601(G/A) A allele of NEDD4L, generating isoform I, was estimated to decrease blood pressure by downregulating Na+ reabsorption. However, a recent functional study showed that isoform I should lead to abnormal Na+ reabsorption increases by antagonistically downregulating epithelial Na+ channel activities. To determine whether the variant rs4149601 A allele is a risk factor for hypertension, has an impact on the antihypertensive response to hydrochlorothiazide, and is associated with orthostatic hypotension, we performed a case-control study of hypertension (n = 1686), a 4-week clinical trial (n = 542), and a case-control study of orthostatic hypotension (n = 793) in Chinese subjects. We found that the A allele was significantly associated with hypertension after appropriate adjustment (odds ratio: 1.39; 95% CI: 1.13 to 1.72; P = 0.002). The blood pressure reduction in A carriers after hydrochlorothiazide treatment was greater than that in GG carriers, with differences of 6.1 mm Hg (P = 0.009) in systolic blood pressure and 2.7 mm Hg (P = 0.027) in diastolic blood pressure. The A allele was significantly associated with orthostatic hypotension after adjustment for cardiovascular risk factors (odds ratio: 0.68; 95% CI: 0.48 to 0.98; P = 0.039). In conclusion, rs4149601 is a genetic risk factor for hypertension and a protective factor against orthostatic hypotension in hypertensive subjects, and the antihypertensive response to hydrochlorothiazide is more sensitive in A allele carriers than in GG carriers. Consequently, the A allele may be a useful marker for predicting hypertension, orthostatic hypotension, and antihypertensive response to hydrochlorothiazide. (Hypertension. 2009; 54: 796-801.)