CD68 and amyotrophic lateral sclerosis: Higher CD68 immunoreactivity in the white matter of motor cortex, medulla, mid-crus cerebri, and lateral and anterior corticospinal tracts of C9-ALS patients (Cooper-Knock et al., 2012) and in the body and genu of corpus callosum of C9-HRE-carrying vs. non-carrying ALS patients has been detected (Cardenas et al., 2017), suggesting that microglial activation and infiltration in the brain might take place at least in late stages of C9-FTLD and C9-ALS.