SEVERE PSEUDOHYPOALDOSTERONISM IN A PAIR OF TWINS NOT ASSOCIATED WITHHYDRAMNIOS

A pair of non-identical twins with severe pseudohypoaldosteronism (PHA ) were followed over a period of 4 years. The diagnosis was based on d ehydration, hyponatremia, hyperkalemia, high urine sodium/potassium ra tios, and high serum concentrations of aldosterone and renin. Sweat an d saliva electrolyte concentrations were high, suggesting multifocal t arget-organ unresponsiveness to mineralocorticoids. No hydramnios was observed during pregnancy. Despite continuous treatment with sodium ch loride and sodium bicarbonate (less than or equal to 20 g/day) and cat ion exchange resin (Kayexalate, sodium polystyrene sulfonate, less tha n or equal to 4 g/kg per day), the children had repeated episodes of d ehydration, hyponatremia, and hyperkalemia. Growth velocity was normal in both twins. Catch-up growth was observed following infancy in the first twin. Normalization of plasma aldosterone, electrolytes, and ren in concentrations was achieved at the age of 9 months.