Abstract: 　Objective　To report a case of systemic pseudoaldosteronism type 1 (PHA1) caused by a new mutation in SCNN1B gene, and provide evidence for early diagnosis and treatment of children with PHA 1. Methods　The clinical manifestations, laboratory tests, diagnosis and treatment results and gene sequencing results were summarized. The literature review of systemic PHA1, especially that caused by SCNN1B gene mutation was performed. Results　The child, female, 4 years and 3 months old, due to "recurrent shock, electrolyte imbalance, rash, pneumonia for 4 years, recurrence with aggravation of 9 days." The child was diagnosed with pseudoaldosteronism at the age of 1 month. She was repeatedly taking dehydrated shock, low sodium, high potassium, acidosis, and repeated lower respiratory tract infection and rash even after being treated by polystyrene sulfonate and sodium citrate. After admission, she was treadted by expanding blood volume, correct acidosis, and actively fight infection, and taking sodium citrate and calcium polystyrene sulfonate orally. The results of gene sequencing showed that there was a c.118C>T missense mutation in the second exon of the SCNN1B gene coding region, and a c.776+1G>A missense mutation in the fourth intron. The two mutations were not reported in the literature in the HGMD database, ESP6500siv2_ALL, Thousand Human Genome (1000g2015aug_ALL) and dbSNP147 database. No mutations associated with high IgE syndrome were detected. Literature search result found no cases of systemic PHA1 caused by SCNN1B mutation in China. A total of 4 cases were reported in foreign literature, the onset age was 3 d~3 w and the onset symtoms were vomiting, poor response, shock, dehydration, hyperkalemia, hyponatremia, metabolic acidosis, running nose, repeated lower respiratory tract infection. In the 4 cases, one patient died and the remaining three survived. Conclusion　PHA1, especially cause by SCNN1B gene mutation, is rare. It is a autosomal recessive inheritance diease. Neonates with refractory hyperkalemia and metabolic acidosis should consider PHA1. Genetic testing can help to confirm the diagnosis and prognosis.

Key words: 　pseudoaldosteronism;　SCNN1B gene;　gene diagnosis;　hyperkalemia;　hyponatremia