Beyond the well-documented role played by rare deleterious TTN mutations in causing cardiomyopathies27, including arrhythmogenic right ventricular dysplasia38, 39, and skeletal myopathies, there is growing evidence for the role of deleterious TTN variants in conduction defects, in the presence or absence of cardiomyopathy and sudden cardiac death40, 41. The gene discussed is TTN; the disease is cardiomyopathy.