1. The Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK
2. Medical Genetics Unit, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
3. Department of Protein Science, KTH-Royal Institute of Technology, 11428 Stockholm, Sweden
4. Translational Mass Spectrometry Research Group, Genetics & Genomic Medicine Department, UCL Institute of Child Health, London WC1N 1EH, UK
5. Science for Life Laboratory, Department of Protein Science, KTH-Royal Institute of Technology, 11428 Stockholm, Sweden