Potential Contribution of DES (p.Leu88Met) and MYH7 (p.Arg787His) Variants to Familial Restrictive Cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is a rare, severe cardiac disease with a heterogeneous genetic basis. Both genetic and nongenetic factors contribute to RCM pathogenesis. Identifying the underlying molecular causes is important for diagnosis and family screening. In this study, we investigated the genetic basis of RCM in a 52-year-old woman with a family history of RCM and heart disease. METHODS: Genetic predisposition was evaluated using whole-exome sequencing (WES). Candidate variants identified in the proband were validated by Sanger sequencing and interpreted using bioinformatics tools and the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines. RESULTS: Two heterozygous missense variants were identified: a novel DES c.262C > A (p.Leu88Met) variant and a previously reported MYH7 c.2360G > A (p.Arg787His) variant. The DES variant was absent from population databases and was classified as a variant of uncertain significance, whereas the MYH7 variant has been reported in the cardiomyopathy spectrum, primarily in hypertrophic cardiomyopathy. Although both variants may be relevant to the participant's phenotype, their contribution remains uncertain without segregation and functional studies. CONCLUSION: These findings expand the spectrum of DES and MYH7 variants observed in cardiomyopathy and highlight the need for further segregation and functional analyses to clarify their clinical significance in RCM. Identifying the genetic basis of RCM in this family may improve screening strategies and guide clinical management.