A Patient With Primary Pseudo-Hypoaldosteronism Type I With Severe Hyperkalemia

TANGARI SAREDO, ANA; FERNÁNDEZ, IVANA; TILITZKY, SANDRA; RIEPE, FELIX; ESTEVANEL, ANA; DEL REY, GRACIELA; RATTO, VIVIANA

Montevideo

Congreso; XXIII Annual Meeting of the Pediatrics Endocrinology Latinoamerican Society (SLEP); 2012

Sociedad Latinoamericana de Endocrinología Pediátrica

Primary pseudo-hypoaldosteronism type I (PHA1) due to mutations in the mineralocorticoid receptor gene (NR3C2) presents as milder and transient salt-wasting syndrome caused by kidney aldosterone resistance; whereas mutations in the epithelial sodium channel (ENaC) subunits coding genes, determine a severe and persistent systemic form. Objective: We report a 2yrs-old boy with PHA1 kidney phenotype, who requires near surveillance because of persistent severe hyperkalemia. Results: A 3-week-old patient born to healthy unrelated parents was admitted with failure to thrive and dehydration. Laboratory: Na:120 mEq/l(132-145), K:7.79mEq/l(3.6-5.9), 17-hydroxyprogesterone: 1,2 ng/ml(<4,0), cortisol: 13,9ug/dl  Aldosterone: 4300pg/ml (50-900) and plasmatic renin activity (PRA) > 15 ngAngiotensineI/ml/h. Renal function was normal. The normal kidney ultrasound and the absent of urinary infection  rule out secondary PHA1. A normal sweat test makes the systemic phenotyp e less probable.  Karyotype was normal: 46,XY. No sequence variations were detected by direct sequencing of the NR3C2 gene. Sodium supplementation was required during 4 months, but potassium exchange resins are still required. At 8 mo levels of potassium reach 7mEq/l.  Conclusions: Near follow up due to severe life-threatening hyperkalemia continues to be necessary. Gene dosage study will allow to known if there is an heterozygous NR3C2 deletion. The study of the ENaC gene could be of interest because patients with homozygous mutations of this gene and transient kidney phenotype were reported.