Pathogenetics of Cardiomyopathy

This review summarizes the current state of knowledge on the genetic factors of both primary or Mendelian cardiomyopathies (CMPs) and some of its secondary forms. Dozens of genes with pathogenic/probably pathogenic variants have been described for primary CMPs. In most cases, the spectrum of causal genetic variants is specific for different CMPs, but shared genes and variants are also discovered. On the one hand genetic causes of diseases have not been established for all cases of primary CMPs, but on the other hand pathogenic variants in Mendelian disease genes are also found for its secondary forms. The genetic component in the development of both primary and secondary CMPs was also established during genome-wide association studies (GWAS). Single nucleotide polymorphisms (SNPs) associated with both primary and secondary CMPs are in most cases specific for different types of disease and make a small contribution to an individual’s overall risk. The link between some SNPs and electro- or echocardiogram features of the normal heart has been reported in the population. Most of the CMPs-associated SNPs are localized in non-coding regions of the genome, but they have a regulatory potential, acting in the heart as loci that affect the level of expression (eQTL), splicing (sQTL) or epigenetic modifications. It is noteworthy that the effects of the eQTL and sQTL genotypes in some cases are not equivalent for different anatomical regions of the heart. The phenotype and clinical presentation of CMPs in general can be determined by a wide range of rare pathogenic/probably pathogenic variants with a strong effect and common polymorphisms with a small effect and modified by epigenetic factors.