Ubiquinol cytochrome c reductase hinge protein (UQCRH) is required for the electron transfer between cytochrome c 1 and c of the mitochondrial cytochrome bc 1 Complex (CIII). A two-exon deletion in the human UQCRH gene has recently been identified as the cause for a rare familial mitochondrial disorder. Deletion of the corresponding gene in the mouse ( Uqcrh -KO) resulted in striking biochemical and clinical similarities inclu...