MFN1 and familial dilated cardiomyopathy: DRP1 KO mice exhibited hypertrophy, LV dysfunction [84] and lethal DCM [101]; when conditionally turned off, they also displayed a decrease in both mitochondrial fission (MFF and FIS1) and fusion proteins (MFN1/2 and L-OPA1), confirming an impaired balance in the mitochondrial dynamics machinery of these hearts [101].