Fig. 3. Patient-level motor function as assessed by CHOP INTEND and Bayley gross and fine motor scores.

a, The dashed straight line represents a CHOP INTEND score of 40, which is a score that untreated patients with SMA type 1 rarely achieve in the natural history of the disease⁷. Shading represents the CHOP INTEND values obtained from normal healthy control infants in the NeuroNEXT study with the mean values presented as a solid purple line⁸. NeuroNext infants were 6 months of age or younger and born between 36–42 weeks gestation and were evaluated using the Test of Infant Motor Performance Screening Items (TIMPSI) and CHOP INTEND (for children who scored <41 on TIMPSI)⁸. The dashed gray line represents the mean change in CHOP INTEND score observed in the NeuroNEXT study of children with SMA type 1 who did not receive disease-modifying treatments⁸. Children who achieved three consecutive CHOP INTEND scores ≥58 were not tested further. Bayley scales gross motor (b) and fine motor (c) subtests. The Bayley scales gross and fine motor normal ranges (±2 s.d.) are presented in gray highlights. n = 4 males and n = 10 females; mean (s.d.) age at dosing, 20.6 (7.9) days.