While TDP-43 proteinopathy is observed in the nervous system of FTLD and ALS patients, it has also been characterized in primary fibroblasts derived from ALS patients, both sporadic, and with various causative pathogenic variants (in C9orf72, TARDBP, FUS, and SOD1 genes) indicating that fibroblast model reflects the changes observed in human brain to some extent (Sabatelli et al., 2015). Here, C9orf72 is linked to amyotrophic lateral sclerosis.