Lysine codon 78 (AAA) in exon 6 was changed to arginine (AGA) (NM_008142:c.233A>G:p.K78R) using an sgRNA and an ssODN template with CRISPR/Cas9 technology. The mutation is the equivalent of the same human mutation associated with neurodevelopmental disorder with global developmental delay and epilepsy (autosomal dominant intellectual developmental disorder 42). Protein expression from this allele is similar to wildtype.