PFN1 and amyotrophic lateral sclerosis: Regarding ALS, most genes involved in the different phenotypes are very well expressed such as SOD1, VCP (Valosin-containing protein), SQSTM1 (Sequestosome 1), HNRNPA1 (Heterogeneous nuclear ribonucleoprotein A1), and PFN1 (Profilin 1).