Biophysical studies of the purified proteins reported that ALS-linked variants of PFN1 are destabilized relative to wildtype profilin, 1 (Boopathy et al., 2015) with an increased propensity to form insoluble aggregates (Del Poggetto et al., 2015, 2016), implying the mutants disturb normal protein quality control. This evidence concerns the gene PFN1 and amyotrophic lateral sclerosis.