The level of IDH2 protein in failing ischemic human hearts has been reported to be reduced34, an observation which we confirmed in human DCM (Fig. 1c and Supplementary Fig. 1d) and Mlp−/− cardiac materials (Fig. 1h and Supplementary Fig. 1e), although this reduction was less pronounced than the decrease in the corresponding level of mRNA. Here, CSRP3 is linked to familial dilated cardiomyopathy.