CRISPR/Cas9 technology replaced exon 2 with a modified exon 2 containing an A to T missense mutation (c.349A>T) which results in an isoleucine to phenylalanine substitution at amino acid 117 (p.I117F) and a loxP-flanked neomycin-resistance gene following the mutant exon 2. The neomycin resistance gene was removed via cre-mediated recombination. The p.I117F mutation correlates to the p.I151F mutation in human. (J:344096)