The iPSC9 lines were previously determined to contain the 5′‐GGGGCC‐3′ hexanucleotide repeat expansions 39. We found the efficiency of oligodendrocyte‐lineage specification and differentiation from mutant lines comparable with control lines in respect to generation of enriched numbers of O4+‐labeled cells (p > 0.15), which exhibit high coexpression of MBP (p > 0.91) and little overlapping PDGFRα labeling (p > 0.82) versus control iPS lines (Supporting Information Fig. 1A, 1B). Similarly, few PDGFRα+‐OPCs persist in 3‐week old differentiation cultures versus control cells (p > 0.29; Supporting Information Fig. 1C).
