The Diagnostic Value of Copy Number Variants in Genetic Cardiomyopathies and Channelopathies.

Sudden cardiac death represents an unexpected death for which a strong underlying genetic background has been described. The primary causes are identified in cardiomyopathies and channelopathies, which are heart diseases of the muscle and electrical system, respectively, without coronary artery disease, hypertension, valvular disease, and congenital heart malformations. Genetic variants, especially single nucleotide variants and short insertions/deletions impacting essential myocardial functions, have shown that cardiomyopathies display high heritability. However, genetic heterogeneity, incomplete penetrance, and variable expression may complicate the interpretation of genetic findings, thus delaying the management of seriously at-risk patients. Moreover, recent studies show that the diagnostic yield related to genetic cardiomyopathies ranges from 28 to 40%, raising the need for further research. In this regard, investigating the occurrence of structural variants, especially copy number variants, may be crucial. Based on these considerations, this review aims to provide an overview of copy number variants identified in cardiomyopathies and discuss them, considering diagnostic yield. This review will ultimately address the necessity of incorporating copy number variants into routine genetic testing for cardiomyopathies and channelopathies, a process increasingly enabled by advances in next-generation sequencing technologies.