AKT1 and familial dilated cardiomyopathy: The functional consequences of TTN variants have been extensively evaluated in the context of dilated cardiomyopathy (DCM).25–29 In this context, one study reported the association of a TTN truncating variant with decreased growth factor signaling pathway readouts, such as diminished phosphorylation of MAPK and AKT,28 which are pertinently downstream of PTEN signaling.