FUS and amyotrophic lateral sclerosis: In the ALS zebrafish model developed by Armstrong et al, they used the CRISPR-Cas9 system to introduce point mutations in the TARDBP and FUS genes; providing evidence that the generation of human disease induced by point mutations can be imitated with knock-in lines developed by homology-directed repair (HDR) following CRISPR-Cas9 [53, 55].