MFN1 and cardiomyopathy: Not surprisingly, as Drp1 deficiency resulted in cardiomyopathy and mitochondrial morphology changes in cardiac-specific Drp1-KO (Song et al., 2015a), significant changes in mitochondrial morphology and abnormal cardiac remodeling were also observed in the hearts of Mfn1/2 DKO mice (Song et al., 2015a).