Most recently, however, approximately 25% of familial and 18% of sporadic DCM cases have been associated with truncating mutations in the TTN gene encoding titin (Herman et al, 2012), an extensively modular sarcomeric protein of more than 35,000 amino acids containing many repeating fibronectin-like and Ig-like domains (LeWinter et al, 2007; Chauveau et al, 2014). The gene discussed is TTN; the disease is familial dilated cardiomyopathy.