These cardiomyopathies are often associated with mutations in mtDNA encoded Complex I subunit genes NADH-ubiquinone oxidoreductase chain 1 and 5 (MT-ND1 and 5) and nuclear-encoded Complex I subunit genes such as NADH: ubiquinone oxidoreductase core subunits S2 (NDUFS2), V2 (NDUFV2) or A2 (NDUFA2). The gene discussed is NDUFS2; the disease is cardiomyopathy.