Clinical and Genetic Heterogeneity of HCM: The Possible Role of a Deletion Involving MYH6 and MYH7

Background/Objectives: Pediatric hypertrophic cardiomyopathy (HCM) is the most common genetic myocardial disorder in children and a leading cause of sudden cardiac death (SCD) among the young. Its phenotypic variability, driven by incomplete penetrance and variable expressivity, presents significant challenges in diagnosis and clinical management. Methods: In this study, we report a unique case of a 16-month-old female diagnosed with HCM caused by a rare genetic deletion. Molecular analysis was performed using a multigene panel and chromosomal microarray analysis (CMA). Results: Molecular tests identified a 30 kb deletion encompassing the MYH6 and MYH7 genes. These genes are critical components of sarcomeric architecture, with known associations to HCM and other cardiomyopathies. Conclusions: This case underscores the clinical and genetic heterogeneity of HCM, highlighting the importance of considering genomic deletions involving key sarcomeric genes in the diagnostic evaluation.