[1] Univ Cape Town, Sch Child & Adolescent Hlth, Red Cross Childrens Hosp, Dept Paediat Neurol, ZA-7925 Cape Town, South Africa
[2] Guys Hosp, DNA Diagnost Lab, London SE1 9RT, England
[3] UCL, Inst Child Hlth, Dubowitz Neuromuscular Ctr, London, England
[4] Univ Wurzburg, Inst Human Genet, Wurzburg, Germany
[5] Univ Cape Town, Red Cross Childrens Hosp, Dept Paediat Pathol, ZA-7925 Cape Town, South Africa
[6] Univ Cape Town, Dept Mol Genet, ZA-7925 Cape Town, South Africa
[7] Bambino Gesu Pediat Hosp, Mol Med Unit, Rome, Italy
[8] Childrens Hosp Philadelphia, Dept Pediat Neurol, Philadelphia, PA 19104 USA
[9] Newcastle Univ, Int Ctr Life, Inst Human Genet, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[10] Robert Jones & Agnes Hunt Orthopaed Hosp, Ctr Inherited Neuromuscular Disorders, Oswestry SY10 7AG, Shrops, England
[11] St Thomas Hosp, Dept Paediat Neurol, Evelina Childrens Hosp, London, England
[12] Guys Hosp, DNA Diagnost Lab, London SE1 9RT, England