Discovered in a patient with hypertrophic cardiomyopathy by Arimura et al., their data suggested that the R4344Q mutation impairs binding to Titin Z8-Z9 and reduces incorporation of transfected obscurin Ig58-Ig59 into the sarcomeric Z-disc of neonatal rat cardiomyocytes (9). Here, TTN is linked to hypertrophic cardiomyopathy.