S100A4 and amyotrophic lateral sclerosis: Furthermore, S100A4 shows a trend to increase also in a fibroblast line derived from a patient carrying the FUS p.R521C pathogenic variant (Additional file 1: Figure S1a) and from patients with the TARDBP p.Q303H and p.A382T mutations (Additional file 1: Figure S1b), suggesting that S100A4 is upregulated in fibroblasts regardless of the ALS condition and gene mutation carried.