The in vivo data from our long-term study in the hSOD1-ALS mice suggest that CRISPR/Cas9 genome editing could be developed as an effective therapeutic approach, with an acceptable risk for treating devastating and uniformly fatal diseases with rapid progression, such as SOD1-A4V linked ALS, which has only 1 year survival after disease onset2,3. Here, SOD1 is linked to amyotrophic lateral sclerosis.