This allele from project Xkr4-8176J-F8924 was generated at The Jackson Laboratory by injecting Cas9 RNA and 4 guide sequences CTCCCAATTCAGAAACCAAA, CCTCCAGCTGTCACTTTAAC, ACAGTCTTACTAGCTCAGTT and GTACGAAAGGAAAATGACTT, which resulted in a 278 bp deletion beginning at Chromosome 1 negative strand position 3,421,962 bp, CTTTGGAGTTTGAATTTCAA, and ending after AAGGTAAGGATTTGCCATTT at 3,421,685 bp (GRCm38/mm10). This mutation deletes exon 2 and 78 bp of flanking intronic sequence including the splice acceptor and donor. In addition there is a 6 bp deletion (TTTAAC) in the intron 95 bp before the deletion that will not alter the effect of the exon deletion. This mutation is predicted to cause a change of amino acid sequence after residue 266 and early truncation 26 amino acids later.