Visit 1: Patients arrived at that hospital at 7:00 am, vital signs were collected and a complete neuromuscular evaluation was carried out (gross motor function measure score sheet (GMFM-88), 6MWT, pre-CPET questionnaire (demographics, physical activity level, risk assessment, asthma/atopy/smoking history, family history), pulmonary function tests and CPET. Following the evaluation, at approximately 9 am, the patient started infusion of ERT.