Replication of the screen (n = 3 independent differentiations) identified a significant effect of ALS variants (P = 0.0008), with a decrease in LD50 survival in donors harboring SOD1 (P = 0.002), TDP43 (P = 0.002), UBQLN2 (P = 0.0003), VCP (P = 0.011) and C9ORF72 (P = 0.005) mutations (Fig. 1t). Here, UBQLN2 is linked to amyotrophic lateral sclerosis.