Background: The study aimed to analyze genes involved in Mendelian forms of low-renin hypertension in Chinese early-onset hypertensive patients.
Methods: A panel of nine genes, namely SCNN1B, SCNN1G, WNK1, WNK4, KLHL3, CUL3, nuclear receptor subfamily 3, group C (NR3C)1, NR3C2, and HSD11B2 were screened by targeted resequencing in 260 Chinese early-onset hypertensive patients. Additionally, exon 13 of both SCNN1B and SCNN1G was sequenced in an independent cohort of 506 Chinese early-onset hypertensive patients.
Results: About 81 nonrare and 41 rare variants were, respectively, detected in 221 (85.0%) and 39 (15.0%) patients from the cohort of 260. Of the total 766 patients, those with rare variants in exon 13 of either SCNN1B or SCNN1G had a significantly earlier onset of hypertension (24.7 ± 7.5 vs. 29.0 ± 7.7 years, P = 0.015) and lower serum potassium (3.57 ± 0.59 vs. 3.96 ± 0.41 mmol/l, P = 0.007) than those without rare variants. However, other identified rare variants had no effects on clinical expression. Seven patients (0.91%) were diagnosed with Liddle's syndrome, and the Liddle's syndrome prevalence was 1.72% among the 407 patients with hypertension diagnosed before the age of 30. Genetic screening of the probands' relatives identified 10 additional Liddle's syndrome patients. Treatment of Liddle's syndrome patients with amiloride resulted in normalization of both blood pressure and serum potassium.
Conclusion: Liddle's syndrome appears to be the most common low-renin Mendelian hypertension in young Chinese hypertensive patients. Sequencing exon 13 of both SCNN1B and SCNN1G is highly advisable in patients with early-onset and low-renin hypertension.