Establishing Walking-related Digital Biomarkers in Rare Childhood Onset Progressive Neuromuscular Disorders

Who May Qualify: - Genetic confirmation of disease (DMD, SMA) or healthy control - Able to walk independently at least 25 meters - Ongoing corticosteroids therapy or initiation of corticosteroid therapy in the previous 3 months for DMD - Stable dose of FDA approved SMN up-regulator therapy or in an open-label extension phase of a study treatment for at least 6 months for SMA or gene replacement at enrollment for SMA or DMD participants. Who Should NOT Join This Trial: - Use foot orthoses or assistive devices for community ambulation or a mobility device for community navigation - Use investigational medications intended for treatment of NMD within 30 days - Prior to study entry had an injury or surgery that would impact gait within the previous 3 months Always talk to your doctor about whether this trial is right for you.