[1] St James Univ Hosp, Leeds Inst Mol Med, Leeds LS9 7TF, W Yorkshire, England
[2] St James Univ Hosp, Yorkshire Reg Genet Serv, Leeds LS9 7TF, W Yorkshire, England
[3] Natl Res Ctr, Human Genet & Genome Res Unit, Dept Clin Genet, Cairo, Egypt
[4] Univ Toronto, Hosp Sick Children, Dept Pediat, Div Clin & Metab Genet, Toronto, ON M5G 1X8, Canada
[5] Sheffield Childrens Hosp, Dept Paediat Neurol, Sheffield, S Yorkshire, England
[6] Bambino Gesu Pediat Hosp, Mol Med Unit, Rome, Italy
[7] Sheffield Childrens Hosp, Dept Paediat Bone Dis, Sheffield, S Yorkshire, England
[8] Royal Infirm, Dept Ophthalmol, Glasgow G31 2ER, Lanark, Scotland
[9] Great Ormond St Hosp Sick Children, Dept Radiol, London WC1N 3JH, England
[10] Natl Res Ctr, Human Genet & Genome Res Unit, Human Cytogenet Dept, Cairo, Egypt
[11] Univ Toronto, Hosp Sick Children, Div Pathol, Dept Pediat Lab Med, Toronto, ON M5G 1X8, Canada
[12] Royal Manchester Childrens Hosp, Dept Paediat Neurol, Manchester M27 1HA, Lancs, England
[13] Great Ormond St Hosp Sick Children, Dept Paediat Neurol, London WC1N 3JH, England
[14] Univ Hosp Dusseldorf, Dept Gen Paediat, Dusseldorf, Germany
[15] Montagu Hosp, Dept Paediat, Mexborough, England
[16] Great Ormond St Hosp Sick Children, Dept Clin & Acad Ophthalmol, London WC1N 3JH, England
[17] Inst Child Hlth, London, England
[18] Royal Hosp Sick Children, Fraser Allander Neurosci Unit, Glasgow G3 8SJ, Lanark, Scotland
[19] Royal Hallamshire Hosp, Dept Ophthalmol, Sheffield S10 2JF, S Yorkshire, England
[20] Univ Toronto, Hosp Sick Children, Dept Ophthalmol & Vis Sci, Toronto, ON M5G 1X8, Canada
[21] Royal Hosp Sick Children, Duncan Guthrie Inst Med Genet, Glasgow G3 8SJ, Lanark, Scotland
[22] Vrije Univ Amsterdam, Med Ctr, Dept Child Neurol, Amsterdam, Netherlands
[23] Bradford NHS Trust, Dept Paediat, Bradford, W Yorkshire, England