Loss-of-function DNA sequence variant in the CLCNKA chloride channel implicates the cardio-renal axis in interindividual heart failure risk variation

Thomas P. Cappola, Scot J. Matkovich, Wei Wang, Derek Van Booven, Mingyao Li, Xuexia Wang, Liming Qu, Nancy K. Sweitzer, James C. Fang, Muredach P. Reilly, Hakon Hakonarson, Jeanne M. Nerbonne, Gerald W. Dorn

Research output: Contribution to journalArticlepeer-review

80 Scopus citations


Common heart failure has a strong undefined heritable component. Two recent independent cardiovascular SNP array studies identified a common SNP at 1p36 in intron 2 of the HSPB7 gene as being associated with heart failure. HSPB7 resequencing identified other risk alleles but no functional gene variants. Here, we further show no effect of the HSPB7 SNP on cardiac HSPB7 mRNA levels or splicing, suggesting that the SNP marks the position of a functional variant in another gene. Accordingly, we used massively parallel platforms to resequence all coding exons of the adjacent CLCNKA gene, which encodes the Ka renal chloride channel (ClC-Ka). Of 51 exonic CLCNKA variants identified, one SNP (rs10927887, encoding Arg83Gly) was common, in linkage disequilibrium with the heart failure risk SNP in HSPB7, and associated with heart failure in two independent Caucasian referral populations (n = 2,606 and 1,168; combined P = 2.25 × 10-6). Individual genotyping of rs10927887 in the two study populations and a third independent heart failure cohort (combined n = 5,489) revealed an additive allele effect on heart failure risk that is independent of age, sex, and prior hypertension (odds ratio = 1.27 per allele copy; P = 8.3 × 10-7). Functional characterization of recombinantwild-typeArg83 and variant Gly83 ClC-Ka chloride channel currents revealed ≈50% loss-of-function of the variant channel. These findings identify a common, functionally significant genetic risk factor for Caucasian heart failure. The variant CLCNKA risk allele, telegraphed by linked variants in the adjacent HSPB7 gene, uncovers a previously overlooked genetic mechanism affecting the cardiorenal axis.

Original languageEnglish (US)
Pages (from-to)2456-2461
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number6
StatePublished - Feb 8 2011


  • Cardiomyopathy
  • Genetic association

ASJC Scopus subject areas

  • General


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