A Missense Mutation in the Extracellular Domain of αENaC Causes Liddle Syndrome.

Détails

ID Serval
serval:BIB_D902F01DA761
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
A Missense Mutation in the Extracellular Domain of αENaC Causes Liddle Syndrome.
Périodique
Journal of the American Society of Nephrology
Auteur(s)
Salih M., Gautschi I., van Bemmelen M.X., Di Benedetto M., Brooks A.S., Lugtenberg D., Schild L., Hoorn E.J.
ISSN
1533-3450 (Electronic)
ISSN-L
1046-6673
Statut éditorial
Publié
Date de publication
2017
Peer-reviewed
Oui
Volume
28
Numéro
11
Pages
3291-3299
Langue
anglais
Résumé
Liddle syndrome is an autosomal dominant form of hypokalemic hypertension due to mutations in the β- or γ-subunit of the epithelial sodium channel (ENaC). Here, we describe a family with Liddle syndrome due to a mutation in αENaC. The proband was referred because of resistant hypokalemic hypertension, suppressed renin and aldosterone, and no mutations in the genes encoding β- or γENaC. Exome sequencing revealed a heterozygous, nonconservative T>C single-nucleotide mutation in αENaC that substituted Cys479 with Arg (C479R). C479 is a highly conserved residue in the extracellular domain of ENaC and likely involved in a disulfide bridge with the partner cysteine C394. In oocytes, the C479R and C394S mutations resulted in similar twofold increases in amiloride-sensitive ENaC current. Quantification of mature cleaved αENaC in membrane fractions showed that the number of channels did not increase with these mutations. Trypsin, which increases open probability of the channel by proteolytic cleavage, resulted in significantly higher currents in the wild type than in C479R or C394S mutants. In summary, a mutation in the extracellular domain of αENaC causes Liddle syndrome by increasing intrinsic channel activity. This mechanism differs from that of the β- and γ-mutations, which result in an increase in channel density at the cell surface. This mutation may explain other cases of patients with resistant hypertension and also provides novel insight into ENaC activation, which is relevant for kidney sodium reabsorption and salt-sensitive hypertension.

Mots-clé
Epithelial Sodium Channels/genetics, Humans, Liddle Syndrome/genetics, Mutation, Missense, Pedigree, ENaC, electrophysiology, genetic renal disease, hypertension, hypokalemia
Pubmed
Web of science
Open Access
Oui
Création de la notice
28/08/2017 8:33
Dernière modification de la notice
20/08/2019 15:58
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