Interestingly, we observe a similar reduction in canonical PTEN downstream signaling readouts (AKT and ERK) as was observed in DCM-TTNtv-related studies.28 Although this was surprising and contrary to our expectations given the decreased level of PTEN and in the context of an overgrowth syndrome, we suspect that the cells activate negative feedback loops to circumvent the contact inhibition. Here, MAPK1 is linked to familial dilated cardiomyopathy.