C9orf72 and amyotrophic lateral sclerosis: In fact, GCI pathology in the gray and white matter of the spinal cord, precentral gyrus, and middle frontal gyrus is reported as a highly characteristic feature of almost all ALS—TDP cases, including sporadic and genetic forms with mutations in C9orf72, TARDBP, and OPTN (Brettschneider et al., 2013, 2014; Lorente Pons et al., 2020; Nolan et al., 2020).