As stated by the authors, it has been traditionally understood that neopterin is formed and secreted by immune cells upon stimulation by inflammatory mediators, namely interferon gamma (IFN-γ) and interleukin 1 beta, hydrogen peroxide, and others (for a review see Ghisoni et al., 2015b); compounds known to be increased in the biological fluids of patients affected by ALS (Vu and Bowser, 2017; Jin et al., 2020). This evidence concerns the gene IFNG and amyotrophic lateral sclerosis.