Clinical and Biochemical Characteristics of Pseudohypoaldosteronism Type 1 with and Without Genetic Mutations: A...

Background/Objectives: Pseudohypoaldosteronism type 1 (PHA-1) is a rare disorder characterized by aldosterone resistance, leading to hyponatremia, hyperkalemia, and elevated renin and aldosterone levels in neonates and infants. While genetic mutations in NR3C2 (mineralocorticoid receptor, MR) and SCNN1A/B/G (epithelial sodium channel, ENaC) are established causes of primary PHA-1, cases without detectable mutations have also been reported. This study aimed to compare the clinical characteristics of genetically confirmed PHA-1 cases-with or without mutations-and to assess genotype-phenotype correlations. Methods: A literature review was conducted using the Medline database, covering studies published from 1966 to October 2023. Included cases were diagnosed with PHA-1 and had undergone genetic testing for NR3C2 and SCNN1A/B/G. Clinical and biochemical data were compared across three groups: MR, ENaC, and non-mutation. Additional subgroup analysis based on mutation type (truncating vs. non-truncating) was also performed. Results: A total of 164 patients from 64 studies met the inclusion criteria. The ENaC group showed significantly higher serum potassium levels than the MR and non-mutation groups. Serum aldosterone levels were significantly higher in the MR group compared to the non-mutation group. A genotype-phenotype correlation was evident in the ENaC group, with truncating variants associated with more severe hyperkalemia. No such correlation was observed in the MR group. Conclusions: This review highlights distinct clinical features of PHA-1 according to genetic status. Aldosterone levels may aid in guiding decisions regarding genetic testing. Furthermore, variant type in ENaC-related PHA-1 may predict biochemical severity and should be considered in clinical management strategies.