['Four genes responsible for pseudohypoaldosteronism type II (PHA-II) have been identified, thereby facilitating molecular diagnostic testing.', 'A 1-year-old boy with prolonged hyperkalemia, metabolic acidosis, hyperchloremia, growth delay, and mild hypertension was diagnosed with PHA-II based on the detection of exon 9 skipping in CUL3 mRNA. The impaired splicing was the result of a de novo, previously unreported single nucleotide substitution in the splice acceptor site of CUL3 intron 8. Among the four genes reported to be involved in PHA-II, CUL3 was the primary suspect in our patient because in patients with the CUL3 mutation, the onset of disease is often early in infancy and the phenotypes of PHA-II are more severe. Our patient was treated with trichlormethiazide, which inhibits the function of the sodium-chloride co-transporter (NCC), and the outcome was favorable, with correction of body fluids and blood electrolyte homeostasis.'] Does cUL3 gene analysis enable early intervention for pediatric pseudohypoaldosteronism type II in infancy?