Mutational Heterogeneity, Modifier Genes, and Environmental Influences Contribute to Phenotypic Diversity of Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy is one of the leading causes of sudden cardiac death in the < or =35-year age group. The broad phenotypic spectrum encompasses left-dominant and biventricular subtypes, characterized by early left ventricular involvement, as well as the classic right-dominant form, better known as arrhythmogenic right ventricular cardiomyopathy. Mendelian inheritance patterns are accompanied by incomplete penetrance and variable expressivity, the latter manifesting as diversity in morphology, arrhythmic burden, and clinical outcomes.