RYR1 Pathogenic Variant in a Patient With Overlapping Features of Brugada Syndrome and Arrhythmogenic Cardiomyopathy

BACKGROUND: Brugada syndrome (BrS) and arrhythmogenic cardiomyopathy (ACM) may overlap clinically, but shared mechanisms remain unclear. RYR1 mutations have not been previously linked to these arrhythmia syndromes. CASE SUMMARY: A 32-year-old man with a family history of BrS presented with palpitations and positional ventricular tachycardia. Ajmaline testing unmasked a diagnostic type 1 BrS electrocardiographic pattern. Cardiac magnetic resonance showed subtle right ventricular dyskinesia and focal left ventricular fibrosis, meeting borderline ACM criteria. Electrophysiological study showed noninducible ventricular arrhythmias, but premature ventricular contractions were reproducibly provoked in the left-lateral position. After shared decision-making, an implantable cardioverter-defibrillator was implanted for primary prevention. Genetic testing revealed a pathogenic truncating RYR1 variant (p.Arg2920∗). DISCUSSION: This case illustrates a novel association of RYR1 mutation with overlapping BrS-ACM features. Shared connexome and calcium-handling abnormalities may underlie this phenotype. TAKE-HOME MESSAGES: RYR1 mutations may contribute to overlapping BrS-ACM phenotypes. Careful imaging, provocative testing, and genetic assessment can guide management.