In addition, earlier extinction of Prph in developing MNs correlated with progressive degeneration of spinal MNs and NMJs, which indicated that the defects observed in Isl2 mutant mice are relevant to early-onset progressive MN disorders such as SMA and ALS (Amin et al., 2015; Amin et al., 2021; Beaulieu and Julien, 2003; Chen et al., 2013; Gros-Louis et al., 2004; Sabbatini et al., 2021). This evidence concerns the gene ISL2 and amyotrophic lateral sclerosis.