1. From the Mitochondrial Medicine Frontier Program, Division of Human Genetics, Children’s Hospital of Philadelphia (R.D.G., I.Y., S.C., A.C.), and the Department of Pediatrics, University of Pennsylvania Perelman School of Medicine (R.D.G.) — both in Philadelphia; and Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston (A.L.M., H.S., Z.G., T.-L.T., V.K.M.), and the Metabolism Program, Broad Institute, Cambridge (A.L.M., H.S., Z.G., T.L.T., V.K.M.) —...