From MRC Centre for Neuromuscular Diseases (E.M., D.M.K., M.G.H.), Neurogenetic Unit (R.L., M.G.S., R.S., A.H., M.B.D.), Department of Molecular Neuroscience (E.M., M.G.H.), and Department of Clinical and Experimental Epilepsy (S.S., D.M.K.), UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London; Mitochondrial Research Group (P.C.), Newcastle University, Newcastle upon Tyne, UK; and Department of Neurology (G.M.), University of Milan, Italy. (At 2009-05-05)