Exon 2, which contains the ATG translation start codon and is shared amongst all known splice variants, was targeted using an sgRNA and CRISPR/Cas9. The resulting allele has a 17 bp insertion in exon 2, resulting in a reading frame shift and subsequent premature stop codon in exon 3. Immunoblots of extracts from spermatozoa demonstrate the lack of protein expression from this allele.