Figure 1220

Mineralocorticoid resistance with hyperkalemia (pseudohypoaldosteronism) includes at least three clinical subtypes, two of which are hereditary disorders. Pseudohypoaldo-steronism type I (PHA1) is characterized by severe neonatal salt wasting, hyperkalemia, and metabolic acidosis. The diagnosis is supported by elevated plasma renin and plasma aldosterone concentrations. Life-saving interventions include aggressive sodium chloride supplementation and treatment with ion-binding resins or dialysis to reduce the hyper-kalemia. This autosomal recessive form of PHA1 results from inactivating mutations in the a or |3 subunits of the epithelial sodium channel [32]. A milder form of PHA1 with autosomal dominant inheritance also has been described; however, the molecular defect remains unexplained [33]. Adolescents or adults with hyperkalemic, hyperchloremic metabolic acidosis, low-normal renin and aldosterone levels, and hypertension have been recently described and classified as having pseudohypoaldosteronism type II (PHA2) or Gordon's syndrome [34]. Pheno-typically, this disorder is the mirror image of Gitelman's syndrome; however, the thiazide-sensitive cotransporter (NCCT) has been excluded as a candidate gene [35].

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