Serine codon 263 (AGT) in exon 7 (ENSMUST00000106609) or 8 (ENSMUST00000029483) was changed to arginine (CGT) (p.S263R) using an sgRNA (targeting TGGATTGGACTGGAAGTCTCTGG) and an ssODN template with CRISPR/Cas9 technology. The mutation is the equivalent of the same human mutation found in amyotrophic lateral sclerosis (ALS) patients. (J:338078)