Concerns About Clinical Effectiveness of Newborn Screening for Spinal Muscular Atrophy

To the Editor It was with great interest and appreciation that we read the article by Schwartz et al, which reported that functional outcomes and, thus, the response to treatment for spinal muscular atrophy (SMA) were significantly better in the newborn screening cohort than in the unscreened clinical symptom onset group. However, this study had some limitations.