A frameshift mutation in the SCNN1B gene in a family with Liddle syndrome: A case report and systematic review.

ABSTRACT

Liddle syndrome is an autosomal dominant form of monogenic hypertension that is caused by mutations in SCNN1A, SCNN1B or SCNN1G, which respectively encode the α, ß and γ subunits of the epithelial sodium channel. In the present study, DNA was extracted from leukocytes in peripheral blood obtained from all members of a family with Liddle syndrome. Whole­exome sequencing and Sanger sequencing were performed to assess the candidate variant and a co­segregation analysis was conducted. A frameshift mutation in SCNN1B (NM_ 000336 c.1806dupG, p.Pro603Alafs*5) in the family was identified, characterized by early­onset hypertension and hypokalemia. The mutation led to the truncation of the ß subunit of the epithelial sodium channel and a lack of the conservative PY motif. Furthermore, a systematic review of follow­up data from patients with Liddle syndrome with SCNN1B mutations was performed. The follow­up data of 108 patients with pathogenic SCNN1B mutations from 47 families were summarized. Phenotypic heterogeneity was evident in patients with Liddle syndrome and early­onset hypertension was the most frequent symptom. Patients responded well to targeted amiloride therapy with significant improvements in blood pressure and serum potassium concentration. The present study demonstrates that confirmatory genetic testing and targeted therapy can prevent premature onset of clinical endpoint events in patients with Liddle syndrome.