NMJs are disrupted in multiple mouse models of SMA, including the SMNΔ7 model, and NMJ pathology in SMA can take the form of pre-synaptic neurofilament accumulation, post-synaptic immaturity, or denervation of motor endplates depending on the specific degree of vulnerability of distinct muscles to SMN deficiency39–41. Here, SMN2 is linked to proximal spinal muscular atrophy.