To detect any MFN2 variants associated with human heart conditions, MFN2 gene exons were resequenced in DNA samples from 398 subjects with idiopathic/non-ischemic dilated cardiomyopathy (DCM) from the Cincinnati Heart Study (Liggett et al., 2008; Matkovich et al., 2010; Cappola et al., 2011), 286 subjects with hypertrophic cardiomyopathy (HCM) from the Houston Hypertrophic Cardiomyopathy cohort (Osio et al., 2007; Li et al., 2017), and 861 non-affected controls from the Cincinnati cohort. Here, MFN2 is linked to familial dilated cardiomyopathy.