[1] Univ Newcastle Upon Tyne, Mitochondrial Res Grp, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[2] Univ Newcastle Upon Tyne, Inst Human Genet, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[3] Natl Neurol Inst, Unit Mol Neurogenet, Pierfranco & Luisa Mariani Ctr Study Childrens Mi, Milan, Italy
[4] Natl Neurol Inst, Div Biochem & Genet, Milan, Italy