[1] Univ London Imperial Coll Sci & Technol, Fac Med,Dubowitz Neuromuscular Ctr, Div Paediat Obstet & Gynaecol, Dubowtz Neuromuscular Unit,Dept Paediat, London W12 0NN, England
[2] Univ Cagliari, Dept Cytomorphol, I-09124 Cagliari, Italy
[3] Univ Oxford, Dept Human Anat & Genet, Oxford OX1 2JD, England
[4] Univ Essen Gesamthsch, Dept Paediat & Paediat Neurol, D-4300 Essen 1, Germany
[5] Univ Newcastle Upon Tyne, Dept Biochem & Genet, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[6] Univ Durham, Dept Biol Sci, Durham DH1 3HP, England
[7] Univ Bern, Inselspital, CH-3010 Bern, Switzerland
[8] Childrens Hosp New Jersey, Newark, NJ USA
[9] Grp Hosp Pitie Salpetriere, Inst Myol, INSERM, U523, F-75634 Paris, France
[10] Robert Jones & Agnes Hunt Orthopaed Hosp, Dept Histopathol, Oswestry SY10 7AG, Shrops, England