SMN1 and proximal spinal muscular atrophy: Splicing defects were assessed in greater detail by Huo et al. (2014), who used microarrays to monitor splicing at exon–exon junctions and identified strong positive and negative splicing events occurring in laser-captured lumbar motoneurons from severe SMA mice (Smn−/−; SMN2+/+) at time points just preceding spinal motoneuron death (P3-P4) [118].