PFN1 and amyotrophic lateral sclerosis: Very recently, profilin-1 has been associated with a familial form of amyotrophic lateral sclerosis (fALS): three amino acid substitutions of profilin-1, namely C71G, M114T and G118V, have been found to be causative pathogenic mutations for fALS, whereas a fourth mutation, namely E117G, has been proposed to be a moderate risk factor for developing ALS4.