[1] Walton Ctr Neurol & Neurosurg, Dept Neurol Sci, Liverpool L9 7LJ, Merseyside, England
[2] St Marys Hosp, Dept Clin Genet, Manchester M13 0JH, Lancs, England
[3] Walton Ctr Neurol & Neurosurg, Dept Neuropsychol, Liverpool, Merseyside, England
[4] Cent Manchester Hlth Care Trust, Dept Neurosci, Manchester, Lancs, England
[5] Alder Hey Childrens Hosp NHS Trust, Dept Clin Genet, Liverpool, Merseyside, England
[6] Alder Hey Childrens Hosp NHS Trust, Dept Community Paediat, Liverpool, Merseyside, England
[7] Alder Hey Childrens Hosp NHS Trust, Dept Paediat Neurol, Liverpool, Merseyside, England
[8] Walton Ctr Neurol & Neurosurg, Clin Trials Unit, Liverpool, Merseyside, England