In the present study, TDP-43 cytoplasmic accumulations or loss of nuclear TDP-43 was not detected in C9orf72 ALS/FTD iPSC-MG mono-cultures; similar to what has been observed in C9orf72 iPSC patient-derived astrocytes (Zhao et al., 2020). Here, C9orf72 is linked to frontotemporal dementia.