C9orf72 and amyotrophic lateral sclerosis: To investigate if C9orf72 ALS/FTD iPSC-MG respond differently to extracellular stimuli, we treated four controls and three C9orf72 ALS/FTD lines of iPSC-MGs with the bacterial toxin, LPS, commonly used to evoke a general non-specific immune response in vitro and in vivo (Beurel and Jope, 2009; Abud et al., 2017; Furube et al., 2018; Hong et al., 2020).