[1] Univ Newcastle Upon Tyne, Dept Neurol, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[2] Univ Newcastle Upon Tyne, Inst Human Genet, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[3] Newcastle Upon Tyne Hosp NHS Trust, Dept Radiol, Newcastle Upon Tyne, Tyne & Wear, England
[4] Hop La Pitie Salpetriere, INSERM, UR523, Inst Myol, Paris, France