[Dilated cardiomyopathy caused by p.E446K mutation in SCN5A gene]

Area of Science:

• Cardiology
• Genetics
• Molecular Biology

Background:

• Dilated cardiomyopathy (DCM) is a primary myocardial disorder causing heart enlargement and impaired contractility, frequently leading to heart failure and transplantation.
• Familial forms account for 20-30% of DCM cases, underscoring its genetic heterogeneity with over 100 implicated genes.
• Mutations in the SCN5A gene have been associated with DCM, particularly when accompanied by cardiac conduction defects and arrhythmias.

Observation:

• This study presents a clinical case of dilated cardiomyopathy in two generations of a family.
• The affected individuals exhibited progressive atrioventricular (AV) block, atrial fibrillation, and mild left ventricular hypertrophy.
• A specific mutation, p.E446K, in the SCN5A gene was identified in conjunction with DCM and cardiac arrhythmias.

Findings:

• The p.E446K mutation in the SCN5A gene was observed in patients with dilated cardiomyopathy and significant cardiac arrhythmias.
• The observed phenotype included progressive AV block and atrial fibrillation, consistent with SCN5A-related cardiac disorders.
• A congenital heart defect, specifically an atrial septal defect, was present in the family but did not co-segregate with the SCN5A mutation or DCM.

Implications:

• This case reinforces the role of SCN5A gene mutations in the pathogenesis of dilated cardiomyopathy and associated arrhythmias.
• Understanding the genetic basis of DCM, including specific mutations like SCN5A p.E446K, is crucial for accurate diagnosis and genetic counseling.
• Further research is warranted to elucidate the complete spectrum of SCN5A-related cardiomyopathies and the potential influence of other genetic or environmental factors on disease presentation.