Moreover, there is an altered expression of several proteins (angiogenin, cystatin C, insulin growth factor 1, galectin 1, hepatocyte growth factor, progranulin, interleukin-6, laminin 1, TNF-alpha, ubiquitin, valosin-containing protein, TDP-43, and vascular endothelial growth factor) in the skin of ALS patients [15]. This evidence concerns the gene GRN and amyotrophic lateral sclerosis.