Genetic screening of SCNN1B and SCNN1G genes in early-onset hypertensive patients helps to identify Liddle syndrome

Background: Liddle syndrome is an autosomal dominant form of monogenic hypertension. Phenotypic variability makes it difficult to identify patients with Liddle syndrome, resulting in misdiagnosis and severe complications at early age. Objectives: To identify mutation in SCNN1B and SCNN1G genes in an adolescent with suspicious Liddle syndrome and his family members and to explore the screening target subjects of Liddle syndrome. Methods: Genetic analysis of the C-terminus of SCNN1B and SCNN1G genes was conducted in an adolescent, with treatment-resistant hypertension and hypokalemia, who was suspected of having Liddle syndrome, and his family members. A Medline research of the reported cases with Liddle syndrome was also performed. Results: A recurrent SCNN1B mutation, c.1853C>A (p.P618H), was detected in the 19-year-old male patient, and family screening identified five additional members who were heterozygous for the mutation. The diagnosis of Liddle syndrome was made in all affected individuals. Despite the phenotypic variability, a systematic review of 54 reported index cases revealed the early-onset hypertension, aged no more than 30 years, as a common feature. Conclusions: Genetic screening for Liddle syndrome should be considered in hypertensive subjects with early penetrance, maybe no more than 30 years, after exclusion of common secondary causes of hypertension.