<p>Methods and compositions relating to diagnosing and treating cardiomyopathy and particularly relating to methods and compositions for diagnosing and treating arrhythmogenic right ventricular dysplasia/cardiomyophathy (ARVD/C) are described. Provided are methods for screening for, diagnosing or detecting a risk of developing arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) comprising detecting the presence of a transmembrane protein 43 (TMEM43) disease associated variant in a sample of a subject, wherein the presence of a TMEM43 disease variant is indicative that the subject has ARVD/C or an increased risk of developing ARVD/C compared to an individual having wild type TMEM43.</p>
