In iPSMNs, whilst non-TDP-43 ALS (SOD1 and FUS mutant) iPSMNs showed only a modest, non-significant increase in p53 (NES = + 2.0, p = 0.25), TDP-43 ALS iPSMNs exhibited strong and significant p53 upregulation (p53 NES = + 14.2, p < 0.001). Here, SOD1 is linked to amyotrophic lateral sclerosis.