Pseudohypoaldosteronism type 1

**Definition:** Pseudohypoaldosteronism type 1 (PHA1) are rare forms of mineralocorticoid resistance. PHA1 presents in the newborn with renal salt wasting, failure to thrive and dehydration. Two clinical forms have been described: i) a renal form (renal PHA1) that improves with age and in which mineralocorticoid resistance is restricted to the kidney, and ii) a generalised severe form (generalised PHA1) that persists into adulthood and in which mineralocorticoid resistance is systemic and salt loss occurs in multiple organs. Inheritance can be autosomal recessive (arPHA1) which is more severe and persistent than the autosomal dominant form (AdPHA1)