Family clinical case report of a MYBPC3 gene sequence variant with diverse phenotypic expressions

In recent years, the results of numerous scientific studies have shifted the focus from phenotypic traits to genotype as the basis for the modern classification of primary cardiomyopathies (CMP). An example of this genotype-specific approach is CMP associated with variants in the MYBPC3 gene, which holds significant clinical relevance. One feature of this heart disease is significant phenotypic heterogeneity. Furthermore, there is high variability in the disease penetrance and expressivity, even among patients with the same MYBPC3 gene variant, which complicates risk stratification, prognosis determination and the personalization of therapeutic approach. This article presents a case of a family with a likely pathogenic MYBPC3 gene variant (rs727503195, c.1790G>A, p.Arg597Gln) in three generations. The described family case clearly demonstrates the significant heterogeneity in the CMP clinical and morphological characteristics associated with MYBPC3 gene variants.