Previous reports suggest that the severity of the effect of FUS mutations on NLS function may correlate with the onset time and severity of ALS disease, as seen in variants such as p.R503fs in a 17-year-old juvenile amyotrophic lateral sclerosis (JALS) patient (Chen et al., 2020) and p.R495QfsX527 in a 19-year-old JALS patient (Belzil et al., 2012). This evidence concerns the gene FUS and juvenile amyotrophic lateral sclerosis.