CRISPR-targeting of exon 37 induces an indel mutation the results in a frameshift mimicking the human variant at amino acid 2608 (R2608fs), which causes a frameshift mutation in exon 37. The allele fails to produced the 440-kDa isoform but expresses a truncated 290-kDa polypeptide and normal levels of 220-kDa isoform. (J:277752)