Alanine codon 1402 (in ENSMUST00000109546) and arginine codons 1403 and 1404 (GCTAGGCGT) were changed to asparagine-valine-tyrosine (AACGTGTAC) (A442_R444delinsNVY) using a crRNA (GAAGCUGCAGAAGCUAGGCGguuuuagagcuaugcuguuuug), a tracrRNA and an ssODN template with CRISPR/Cas9 technology. The mutation, near the ADAMTS cleavage site in the encoded peptide, blocks cleavage. (J:298045)