Exon 13 was targeted using an sgRNA and CRISPR/Cas9 technology, resulting in a 91 bp deletion spanning the 3' end of exon 13 and the 5' end of intron 13. The transcripts expressed from this allele skip the 3'-incomplete exon 13 (resulting in a frameshift and premature termination) and total transcription levels are reduced. (J:280563)