Expert opinion was solicited to specify the treatment mix in the model (i.e., the proportions of patients receiving the different treatments, according to the different SMN2 copies in the NBS screening arm and SMA types in the no NBS screening arm), and published data from pivotal trials was used to estimate the treatment effectiveness [29,30,31,32,33,34,35,36,37]. Here, SMN2 is linked to proximal spinal muscular atrophy.