[1] UCL, Inst Neurol, Dept Mol Neurosci, London WC1N 3BG, England
[2] Robert Debre Univ Hosp, Dept Genet, F-75019 Paris, France
[3] INSERM, U676, F-75019 Paris, France
[4] Liege Univ Hosp, Dept Genet, Liege, Belgium
[5] Univ Lubeck, Dept Neurol, Lubeck, Germany
[6] UCL, MRC Lab Mol Cell Biol, London WC1E 6BT, England
[7] UCL, Inst Child Hlth, Mol Med Unit, London WC1E 6BT, England
[8] UCL, Dept Genet Evolut & Environm, London WC1E 6BT, England