Ability of Muscle Imaging and Motor Function Measure (MFM) to Detect Changes in Disease Progression in Ambulant Spinal Muscular Atrophy Patients Compared to Healthy Volunteers.

This non-drug, single center, 24-week, longitudinal study in ambulant spinal muscular atrophy (SMA) patients and in age- and gender-matched healthy volunteers will assess the detection of disease progression by magnetic resonance imaging (MRI) and the Muscle Function Measure (MFM) test. Each participant will be evaluated in three testing sessions: at baseline, at Week 12 and at Week 24. Both patients and volunteers will undergo MRI scans. Patients will additionally undergo testing of motor function and have blood samples taken for Survival of the Motor Neuron (SMN) genes, proteins and mRNA analysis.