Pseudohypoaldosteronism Type 1b in a Saudi Female Infant Due to Homozygous Variant Gene Mutation in SCNN1A: A Case Report.

Pseudohypoaldosteronism type 1 (PHA1) is a rare, heterogeneous group of disorders characterized by resistance to aldosterone action. We report the case of a 17-day-old Saudi female infant who presented on the third day of life with persistent hyperkalemia, hyponatremia, and metabolic acidosis. Initial evaluation for congenital adrenal hyperplasia was unremarkable. Genetic testing confirmed a novel homozygous variant (c.1522C>T p.(Arg508) chr 12:6458147 in SCNN1 A) in the SCNN1A gene, consistent with the diagnosis of PHA1B, a genetically confirmed subtype of PHA1. Prompt recognition and management of electrolyte disturbances are crucial in these neonates to prevent life-threatening complications.