GRN and amyotrophic lateral sclerosis: Similarly, two recent studies highlighted evidence of mild TDP-43 pathology in 2D ALS-iPSC-derived neuron and 100-day-old GRN knockout neuronal cultures when compared with healthy controls, with the ALS study showing evidence of STMN2 mis-splicing (Bossolasco et al., 2022; Coyne et al., 2021).