1. Department of Health Sciences, Faculty of Medicine, Lund University, Lund, Sweden;
2. Department of Clinical Genetics, Center for Rett Syndrome, Kennedy Center, Rigshospitalet, Glostrup, Denmark;
3. Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia;
4. School of Physiotherapy and Exercise Science, Curtin University, Perth, Western Australia, Australia