A novel mutation of the epithelial Na+ channel causes type 1 pseudohypoaldosteronism.
SourcePediatric Nephrology, 17, 10, (2002), pp. 804-808
Article / Letter to editor
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SubjectElucidation of hereditary disorders and their molecular diagnosis; Disturbances in biochemical and functional development of the kidney during childhood.; Opheldering van erfelijke ziekten en hun moleculaire diagnostiek; Stoornissen in de biochemische en functionele ontwikkeling van de nier op kinderleeftijd
Type I pseudohypoaldosteronism (PHA-1) is a rare salt wasting syndrome occurring soon after birth, characterized by apathy and severe dehydration accompanied by hyponatremia, hyperkalemia, and metabolic acidosis despite high plasma aldosterone concentrations. The molecular defect involved in the systemic autosomal recessive form of the syndrome has been identified. Mutations in all three genes encoding the epithelial sodium channel (ENaC) lead to a decrease in the channel function, resulting in the disease. We report here two new cases of the autosomal recessive form of PHA-1 in the same family. We found a new homozygous mutation of the gene encoding the alpha ENaC subunit (alphaR492stop). The function of the mutated ENaC channel was assessed in the Xenopus laevis oocyte expression system. The mutant ENaC activity measured with the two-electrode voltage clamp method was drastically decreased compared with the wild type activity, in agreement with the salt-losing phenotype.
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