Snapshot An infant is brought to the pediatrician by his mother due to muscle weakness. The mother reports that the infant’s weakness has progressively worsened. He is unable to sit unsupported, has a weak cry and suck. On exam, there is fasciculations of the tongue and fingers with absent deep tendon reflexes. Molecular genetic testing for the SMN gene is ordered. Introduction Also known as infantile spinal muscle atrophy (SMA) login to view 6 more bullets Epidemiology Commonly presents in the neonatal period Median survival is 7 months login to view 1 more bullet Presentation Symptoms login to view 6 more bullets Physical exam login to view 4 more bullets Evaluation Molecular genetic testing login to view 1 more bullet Electromyography (EMG) login to view 1 more bullet Muscle biopsy Differential Congenital myasthenia syndromes Congenital myopathy Treatment Supportive login to view 2 more bullets Prognosis, Prevention, and Complications 95% death by 18 months of age and 100% by four years of age Development of kyphosis and scoliosis Weakened pulmonary muscles login to view 2 more bullets Malnutrition login to view 1 more bullet Immobility login to view 1 more bullet