THE “SALT-TASTING” NEWBORN

Pseudohypoaldosteronism type 1 (PHA1) is a rare genetic disease due to the peripheral resistance to aldosterone. Clinical spectrum with neonatal onset includes salt loss, hyponatremia, hypochloraemia, hyperkalaemia, metabolic acidosis and increased plasmatic levels of aldosterone. Two forms of the disease - renal and systemic – have been described, which are genetically distinct and with wide clinical expressivity. The most severe generalized PHA1 is caused by mutations in the genes encoding for the subunits of the epithelial sodium channels (ENaC). The paper reports the case of a newborn of the first pregnancy of healthy and consanguineous Sicilian parents, with a clinical and hormonal picture compatible with the diagnosis of generalized PHA1. A novel SCNN1A gene mutation, inherited from both heterozygous, was identified by next generation sequencing (NGS) in the homozygous child. The neonatologist should consider a diagnosis of PHA1 in case of hyponatremia, hyperkalaemia and metabolic acidosis. The diagnostic suspicion was confirmed by the increased plasmatic levels of aldosterone and aldosterone/renin ratio, associated to a poor response to steroid administration. The treatment is based on high doses of sodium chloride, fludrocortisone and glucocorticoids, insulin and ion exchange resins. It may be useful to reduce potassium intake with the use of special formulas. The clinician must gradually balance the doses of drugs on the basis of electrolyte and hormone levels. A multi-disciplinary team and close follow-up evaluations are needed for optimal management of such patients. The present report may broaden the knowledge of the genetic and molecular bases of disease, by improving its clinical characterization and providing useful indications for the treatment of patients. Clinical approach must be personalized, also in relation to long survival and potential multi-organ complications. I