Journal Article

FZJ-2022-01412

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png A Novel Homozygous KLHL3 Mutation as a Cause of Autosomal Recessive Pseudohypoaldosteronism Type II Diagnosed Late in Life

Etges, A. ; Hellmig, N. ; Walenda, G. ; Haddad, B. G.FZJ* ; Machtens, J.-P.FZJ* ; Morosan, T. ; Rump, L. C. ; Scholl, U. I. (Corresponding author)

2022
Karger Basel

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Please use a persistent id in citations: http://hdl.handle.net/2128/31565  doi:10.1159/000521626

Abstract: Introduction: Pseudohypoaldosteronism type II (PHA II) is a Mendelian disorder, featuring hyperkalemic acidosis and low plasma renin levels, typically associated with hypertension. Mutations in WNK1, WNK4, CUL3, and KLHL3 cause PHA II, with dominant mutations in WNK1, WNK4, and CUL3 and either dominant or recessive mutations in KLHL3. Fourteen families with recessive KLHL3 mutations have been reported, with diagnosis at the age of 3 months to 56 years, typically in individuals with normal kidney function. Methods: We performed clinical and genetic investigations in a patient with hyperkalemic hypertension and used molecular dynamics simulations, heterologous expression in COS7 cells, and Western blotting to investigate the effect of a KLHL3 candidate disease mutation on WNK4 protein expression. Results: The patient, a 58-year-old woman from a consanguineous family, showed hypertension, persistent hyperkalemic acidosis associated with severe muscle pain, nephrolithiasis, chronic kidney disease (CKD), and coronary heart disease. Therapy with hydrochlorothiazide corrected hyperkalemia, hypertension, and muscle pain. Genetic analysis revealed a homozygous p.Arg431Trp mutation at a highly conserved KLHL3 position. Simulations suggested reduced stability of the mutant protein, which was confirmed by Western blot. Compared with wild-type KLHL3, cotransfection of p.Arg431Trp KLHL3 led to increased WNK4 protein levels, inferred to cause increased NaCl reabsorption via the thiazide-sensitive carrier and PHA II. Conclusions: Even in patients presenting late in life and in the presence of CKD, PHA II should be suspected if renin levels are low and hyperkalemic acidosis and hypertension are inadequate for CKD stage, particularly in the presence of a suspicious family history

Note: Funding: This study was funded by the Ministerium für Kultur und Wissenschaftder Landes Nordrhein-Westfalen (Rückkehrprogramm),the Stiftung Charité (BIH_PRO_406), and the German ResearchFoundation (DFG, SCHO 1386/2-1; project-ID 431984000, CRC1453), all to U.I.S. It was funded by the Deutsche Forschungsgemeinschaft(German Research Foundation) to J.P.M. (MA 7525/2-1, as part of the research unit FOR 5046, project P2) and by a grantfrom the Interdisciplinary Centre for Clinical Research within thefaculty of Medicine at the RWTH Aachen University (IZKF TN1-3/IA532003). The authors gratefully acknowledge the computingtime granted through JARA on the supercomputer JURECA atForschungszentrum Jülich. Funding agencies had no role in thepreparation of the manuscript.

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Contributing Institute(s):

1. Molekular- und Zellphysiologie (IBI-1)

Research Program(s):

1. 5241 - Molecular Information Processing in Cellular Systems (POF4-524) (POF4-524)

Appears in the scientific report 2022

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