TTN and hypertrophic cardiomyopathy: Titin missense mutations have been identified in DCM and hypertrophic cardiomyopathy cohorts.4,37,38 A causative role for TTN p. W976R in DCM is well supported by cosegregation within a large family and functional data.39,40 However, generally, titin missense mutations are challenging to interpret because rare benign variants are common in normal population cohorts.