A point mutation in exon 8 (NM_172493.2: c.877A>G) was intended to change isoleucine codon 293 (ATT), straddling exons 8 and 9, to valine (GTT) (NP_766081.1:p.I293V), using an sgRNA and ssODN template with CRISPR/Cas9 technology. However, an off-target event also created a 19 bp deletion (TTGCATTGTTGGGGAAGAA) a few bases upstream (NM_172493.2: c.855_873del), resulting in a frameshift and premature stop codon in exon 9, thus changing the effect of the point mutation and creating a knockout allele instead.