Genetic Study of Hypertrophic Cardiomyopathy in Iranian Patients: The Role of a De Novo Variant

Hypertrophic cardiomyopathy is a common cardiac disease diagnosed in young adults and rarely detectable in childhood. Hypertrophic cardiomyopathy exhibits considerable diversity in its clinical and genetic characteristics. To date, mutations in multiple genes associated with HCM have been discovered, with the most common ones being MYBPC3 and MYH7 genes. The present study aimed to utilize whole exome sequencing for conducting a genetic analysis of Hypertrophic cardiomyopathy in four children belonging to Iranian families.

Patients underwent medical evaluation, including clinical assessment, electrocardiography, and echocardiography. Genetic testing was performed after DNA extraction using whole exome sequencing to identify genetic alterations that may be responsible for this disease. In addition, bioinformatic analysis of the genetic changes was carried out using software tools for alignment, variant calling, and interpretation. Finally, the Sanger sequencing method was employed to confirm the genetic variations in the affected individual's family members.

The patients were children presenting with initial symptoms, such as syncope and palpitations. They were diagnosed with Hypertrophic cardiomyopathy type 3 and 4 based on the results of electrocardiography and echocardiography. The genetic testing results revealed a pathogenic de novo mutation (c.1208G>A, p.Arg403Gln) in the MYH7 gene. In addition, another disease-causing homozygous nonsense genetic variation (c.3811C>T, p.Arg1271Ter) was identified in the MYBPC3 gene, resulting in the production of a premature protein.

This study not only expanded the spectrum of genetic variations associated with Hypertrophic cardiomyopathy disease and aided in genetic counseling for families affected by it but also presented the first variations of the sarcomere gene in Iranian children.