MIB1 and cardiomyopathy: Of interest is that myocardial inactivation of Jag1, or combined inactivation of Jag1 and Jag2, or Mib1, leads to thinner ventricular walls, accompanied by reduced cardiomyocyte proliferation, disrupted ventricular chamber patterning, and cardiomyopathy (Luxán et al., 2013; D’Amato et al., 2016).