Onasemnogene abeparvovec was recently approved for the treatment of spinal muscular atrophy (SMA) in children younger than two years; however, clinical trials were primarily completed in children younger than seven months, so practical experience dosing older children began in summer 2019. Here, we look at the safety and efficacy of onasemnogene in seven infants older than seven months who were treated at our center. Overall, onasemnogene appears to be efficacious in children older than seven months and well tolerated. Side effects were similar to those previously reported, although more common and in some cases more severe and more prolonged than seen in the original trials. The impact of age, weight, and other confounding factors on development of side effects still needs to be elucidated.