In addition to neuropathological findings, further evidence for a role of oligodendroglia in ALS/FTD is provided from genetic studies that have identified the oligodendrocyte-specific gene MOBP as a risk factor for ALS (van Rheenen et al., 2016) and a risk variant of MOBP to be associated with more severe white matter degeneration and a clinically more aggressive form of FTD (Irwin et al., 2014). The gene discussed is MOBP; the disease is amyotrophic lateral sclerosis.