The Predictive Value of Achieved Motor Milestones Assessed in 441 Patients with Infantile Spinal Muscular Atrophy Types II and III

Proximal spinal muscular atrophy (SMA) is classified into three main subtypes (I–III), defined by age at onset and achieved motor milestones. As age at onset can be very early in SMA II and III (IIIa, onset