In order to gain insights into HuD regulation in ALS, we took advantage of spinal MNs derived from isogenic pairs of FUS WT and P525L hiPSC lines (hereafter FUSWT and FUSP525L) by inducible expression of a “programming module” consisting of the transcription factors Ngn2, Isl1 and Lhx3 (NIL)31,32. Here, ISL1 is linked to amyotrophic lateral sclerosis.