PFN1 and amyotrophic lateral sclerosis: Exome sequencing studies reveal 8 mutations in the PFN1 gene in both familial and sporadic ALS cases (C71G, G118V, M114T, E117G, T109M, R136W, A20T, Q139L) (Figure 6.1; Wu et al., 2012; Chen et al., 2013; Ingre et al., 2013; Smith et al., 2015; Alkam et al., 2017).