Dermal fibroblast derived iPSCs were generated from two healthy individuals (Con‐1 and Con‐2), three ALS patients carrying the C9orf72 hexanucleotide repeat expansion (C9‐1, C9‐2, and C9‐3) as well as isogenic control lines for C9‐1, C9‐2, and C9‐3 wherein the G4C2 repeat expansion was corrected using CRISPR/Cas9 mediated genome editing (C9‐Δ) (Selvaraj et al., 2018). The gene discussed is C9; the disease is amyotrophic lateral sclerosis.