Renal pseudohypoaldosteronism type 1 – an adult case series including a novel gene variant

Purpose Renal pseudohypoaldosteronism type 1 (PHA1) is a rare disease affecting infants. Symptoms are failure to thrive, vomiting and weight loss. It is caused by gene variants in NR3C2 by which the mineralocorticoid receptor is dysfunctional, and patients develop hyponatremia, elevated plasma aldosterone and renin but have normal blood pressure. Little is known about PHA1in adults. We present four adults with PHA1, their clinical, biochemistry and genetic data. Methods Clinical and biochemical data were collected from the medical files and clinical examination of the participants. Genetic testing was performed. Results Two adult dizygotic twins and their mother, as well as an adult man were included. One of the sisters and the man had had severe hyponatremia and been admitted several times as young infants, treated with sodium chloride and fludrocortisone. All had as adults elevated plasma aldosterone and normal potassium. The females now had normal plasma renin, but it was increased in the male. A novel genetic variant in NR3C2 were found in the twins and their mother (c.1816T > C, p.(Cys606Arg)). All had normal blood pressure and were asymptomatic. Conclusion In adulthood PHA1 seems to be asymptomatic and long-term consequences favorable.