Inclusion Criteria:  Infants of both sexes Suffering from spinal muscular atrophy (diagnosis by genetic study "homozygous deletion of SMN1") Followed up by the Necker Neuromuscular Reference Center (GNMH)  Eligible for innovative therapy (gene therapy or pharmacogenetics)  age of onset of the disease <1 year no severe respiratory impairment (dependence on ventilatory support for more than 16 hours per day) or bulbar involvement decision of treatment by a Multidisciplinary Consultation Meeting national of experts Benefiting from social security scheme Informed consent signed by holders of parental authority and the investigator  Exclusion Criteria:  Non-consent of one of the holders of parental authority Respiratory instability (dependence on ventilatory support for more than 16 hours per day) or hemodynamics Contraindication to innovative therapy History of another disease impacting motor skills (neonatal suffering, etc.)