TTN and familial dilated cardiomyopathy: More recently, our group showed that the prevalence of rare variants in DCM-causing genes was similar in non-alcoholic DCM vs. AC, with a predominance of titin-truncating variants (TTNtv).57 Alcohol-induced cardiomyopathy patients with a TTNtv had an 8.7% absolute reduction in LVEF compared with those with AC but without TTNtv paving the way to support the double-hit hypothesis of DCM arousing from the combination of genetics with environmental factors (Figure 1).