Aspartic acid codon 387 (GAT) was targeted for change to an alanine codon (GCG)(p.D387A) with an sgRNA (targeting TAATACGACTCACTATAGGACAGAACCACACTTTAGAAGGTTTTAGAGCTAGAAATAGCA) and an ssODN template (CCAAGATCTTTTTCATTCAGGCTTGCCAAGGAAGTAACTTCCAGAAAGGAGTGCCTGATGAGGCAGGCTTCGAGCAACAGAACCACACTTTGGAGGTTGCGAGCTCATCTCACAAGAACTATATTCCGGATGAGGCAGACTTTCTGCTGGGAATGGCTACGGTGAAGAACTGCGTTTCCTACCGAGATCCTGTGAATGGA) using CRISPR/Cas9 technology. The mutation creates an uncleavable form of the encoded peptide. (J:296046)