In mice with DCM mutations in cardiac α-myosin heavy chain (S532P and F764L), we found that contractile function of isolated myocytes was depressed, both mutant myosins exhibited reduced ability to translocate actin but similar force-generating capacities, and actin-activated ATPase activities were reduced [32]. The gene discussed is DNAH8; the disease is familial dilated cardiomyopathy.