# Dilated Cardiomyopathy in a Young Patient With an FLNC Gene Mutation

## TL;DR

A young man with no heart history developed severe heart failure due to a rare FLNC gene mutation, emphasizing the need for genetic testing in unexplained cases.

## Contribution

This case report highlights the importance of genetic testing for FLNC mutations in young patients with unexplained dilated cardiomyopathy.

## Key findings

- A 28-year-old male with no cardiovascular history was diagnosed with FLNC-associated dilated cardiomyopathy.
- The identified FLNC variant was likely pathogenic and linked to severe biventricular dysfunction.
- Truncating FLNC mutations are rare but associated with high risk of arrhythmias and sudden cardiac death.

## Abstract

Background: Dilated cardiomyopathy is a leading cause of heart failure and heart transplantation. Among its etiologies, genetic variants account for up to 35% of cases. Variants in the FLNC gene have gained recognition due to their association with a higher risk of major ventricular arrhythmias and sudden cardiac death. Early identification and intervention are critical to improving patient outcomes.

Case Presentation: We present the case of a 28-year-old male with no cardiovascular history who presented with ischemic stroke. Neurological improvement was noted following thrombolysis. Extensive testing ruled out infectious, thrombotic, and autoimmune causes. Subsequent evaluation revealed severe left ventricular systolic dysfunction (ejection fraction of 20%) and biventricular dilated cardiomyopathy. Genetic testing identified a likely pathogenic FLNC variant NM_001458.5(FLNC):c.1156G>T; p.Glu386∗, confirming the diagnosis of FLNC-associated dilated cardiomyopathy.

Discussion: This case highlights the importance of investigating genetic causes in young patients presenting with unexplained dilated cardiomyopathy. Although truncating FLNC mutations are rare, they are associated with adverse outcomes, including major ventricular arrhythmias and sudden cardiac death. Atypical biventricular involvement suggests overlapping phenotypes, complicating the diagnostic process. Advanced imaging modalities, comprehensive management strategies, and early genetic testing are crucial to optimizing patient outcomes.