Danon Disease Manifesting as Arrhythmogenic Right Ventricular Cardiomyopathy: A Case Report

Danon disease is a rare X-linked genetic disorder, manifesting as cardiac hypertrophy, myopathy, and intellectual disability. We report a rare case of arrhythmogenic right ventricular cardiomyopathy (ARVC) in a 28-year-old female with Danon disease. An electrocardiogram (ECG) showed sinus bradycardia and first-degree atrioventricular block; echocardiography revealed a right atrial thrombus, and computed tomography (CT) scan displayed an enlarged right ventricular outflow tract and right atrial thrombosis. Genetic testing identified a novel Lysosomal Associated Membrane Protein 2 (LAMP2) gene variant, confirming the diagnosis of Danon disease. The patient was administered anticoagulants and heart failure medications. This case underscores the importance of considering family history and genetic testing in diagnosing Danon disease with ARVC. This expands the disease's phenotypic spectrum beyond its conventional cardiac manifestations.