Exome sequencing identifies pathogenic and modifier mutations in a child with sporadic dilated cardiomyopathy

Pamela A. Long, Brandon Larsen, Jared M. Evans, Timothy Mark Olson

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Background-Idiopathic dilated cardiomyopathy (DCM) is typically diagnosed in adulthood, yet familial cases exhibit variable agedependent penetrance and a subset of patients develop sporadic DCM in childhood. We sought to discover the molecular basis of sporadic DCM in an 11-year-old female with severe heart failure necessitating cardiac transplantation. Methods and Results-Parental echocardiograms excluded asymptomatic DCM. Whole exome sequencing was performed on the family trio and filtered for rare, deleterious, recessive, and de novo variants. Of the 8 candidate genes identified, only 2 had a role in cardiac physiology. A de novo missense mutation in TNNT2 was identified, previously reported and functionally validated in familial DCM with markedly variable penetrance. Additionally, recessive compound heterozygous truncating mutations were identified in XIRP2, a member of the ancient Xin gene family, which governs intercalated disc (ICD) maturation. Histomorphological analysis of explanted heart tissue revealed misregistration, mislocalization, and shortening of ICDs, findings similar to Xirp2-/- mice. Conclusions-The synergistic effects of TNNT2 and XIRP2 mutations, resulting in perturbed sarcomeric force generation and transmission, respectively, would account for an early-onset heart failure phenotype. Whereas the importance of Xin proteins in cardiac development has been well established in animal models, this study implicates XIRP2 as a novel modifier gene in the pathogenesis of DCM.

Original languageEnglish (US)
Article numbere002443
JournalJournal of the American Heart Association
Volume4
Issue number12
DOIs
StatePublished - Dec 1 2015

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Keywords

  • Dilated cardiomyopathy
  • Genetics
  • Heart failure
  • Pediatrics
  • Whole exome sequencing

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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