Proteomic analysis in Rbm20 knockout (KO) rats at 3 weeks of age—before the development of the DCM phenotype—revealed differential expression of 103 proteins in the Rbm20 KO.46 Many of these proteins are involved in mitochondrial function and metabolism, including the down-regulated enoyl-CoA hydratase 1 (ECH1), pyruvate dehydrogenase kinase 4 (PDK4), aldehyde dehydrogenase 1 family member B1 (ALDH1B1), and 3-hydroxy-3-methylglutaryl-CoA synthase2 (HMGCS2), with Hmgcs2 being the most significantly down-regulated. The gene discussed is ECH1; the disease is familial dilated cardiomyopathy.