Liddle syndrome with a SCNN1B mutation: a case report and systematic review

Liddle syndrome is an autosomal dominant disorder caused by pathogenic gain-of-function variants in genes encoding epithelial sodium channel subunits, including α (SCNN1A), β (SCNN1B), and γ (SCNN1G). Among these, SCNN1B variants are most prevalent, with nearly all previously reported cases presenting with hypertension.

We report a 16-year-old Chinese female patient who presented with hypokalemia without hypertension. Laboratory investigations revealed suppressed plasma renin and aldosterone levels. Genetic sequencing identified a heterozygous SCNN1B variant (c.1852 C > T,p.Pro618Ser), leading to a confirmed diagnosis of Liddle syndrome. We systematically analyzed phenotypic characteristics of SCNN1B-related cases from the PubMed database.

While Liddle syndrome typically manifests with hypertension, hypokalemia, and suppressed renin-aldosterone levels, our analysis demonstrates clinical heterogeneity that may correlate with specific mutation loci. This case highlights the importance of recognizing atypical presentations, particularly in young patients exhibiting isolated hypokalemia. Definitive diagnosis through genetic sequencing is crucial to enable timely initiation of targeted therapy, including ENaC blockade and potassium-sparing diuretics, thereby preventing long-term complications of chronic electrolyte imbalance.