CRISPR-targeting modified exon 16 to humanize the sequence with the amino acid substitutions glycine to arginine at position 676, phenylalanine to tyrosine at position 681, and arginine to histidine at position 684 (G676R, F681Y, R684H) analogous to the Alzheimer's disease associated human mutations KM670/671NL, E693G, I716F. (J:303244)