CRISPR/Cas9 technology generated a CC to GA change resulting in a proline to aspartate substitution at amino acid 1244 (P1244D) as well as a C to T change resulting in an alanine to valine substitution at amino acid 1245 (A1245V). These mutations abolish the key cleavage site and make the protein uncleavable by ADAMTS-3. (J:293055)