Claire L Wood1, Tim Cheetham2. 1. The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK. Electronic address: claire.wood@newcastle.ac.uk. 2. Department of Paediatric Endocrinology, Royal Victoria Infirmary, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK.