Compound and digenic heterozygosity contributes to arrhythmogenic right ventricular cardiomyopathy

J Am Coll Cardiol. 2010 Feb 9;55(6):587-97. doi: 10.1016/j.jacc.2009.11.020.


Objectives: The aim of this study was to define the genetic basis of arrhythmogenic right ventricular cardiomyopathy (ARVC).

Background: Arrhythmogenic right ventricular cardiomyopathy, characterized by right ventricular fibrofatty replacement and arrhythmias, causes sudden death. Autosomal dominant inheritance, reduced penetrance, and 7 desmosome-encoding causative genes are known. The basis of low penetrance is poorly understood.

Methods: Arrhythmogenic right ventricular cardiomyopathy probands and family members were enrolled, blood was obtained, lymphoblastoid cell lines were immortalized, deoxyribonucleic acid was extracted, polymerase chain reaction (PCR) amplification of desmosome-encoding genes was performed, PCR products were sequenced, and diseased tissue samples were studied for intercellular junction protein distribution with confocal immunofluorescence microscopy and antibodies against key proteins.

Results: We identified 21 variants in plakophilin-2 (PKP2) in 38 of 198 probands (19%), including missense, nonsense, splice site, and deletion/insertion mutations. Pedigrees showed wide intra-familial variability (severe early-onset disease to asymptomatic individuals). In 9 of 38 probands, PKP2 variants were identified that were encoded in trans (compound heterozygosity). The 38 probands hosting PKP2 variants were screened for other desmosomal genes mutations; second variants (digenic heterozygosity) were identified in 16 of 38 subjects with PKP2 variants (42%), including desmoplakin (DSP) (n = 6), desmoglein-2 (DSG2) (n = 5), plakophilin-4 (PKP4) (n = 1), and desmocollin-2 (DSC2) (n = 1). Heterozygous mutations in non-PKP 2 desmosomal genes occurred in 14 of 198 subjects (7%), including DSP (n = 4), DSG2 (n = 5), DSC2 (n = 3), and junctional plakoglobin (JUP) (n = 2). All variants occurred in conserved regions; none was identified in 700 ethnic-matched control subjects. Immunohistochemical analysis demonstrated abnormalities of protein architecture.

Conclusions: These data suggest that the genetic basis of ARVC includes reduced penetrance with compound and digenic heterozygosity. Disturbed junctional cytoarchitecture in subjects with desmosomal mutations confirms that ARVC is a disease of the desmosome and cell junction.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Arrhythmogenic Right Ventricular Dysplasia / genetics*
  • Child
  • Desmosomes
  • Female
  • Heterozygote*
  • Humans
  • Male
  • Middle Aged
  • Pedigree*