This spontaneous mutation was identified at The Jackson Laboratory. Sequence analysis of mutant genomic DNA compared with wild type C57BL/6J genomic DNA identified a single nucleotide transition from G to A at nucleotide 24224235 (build NCBI37 or m9). This mutation disrupts the consensus AG dinucleotide of the CAG splice acceptor of the adjacent exon (exon 26 of ENSMUST00000118733). (J:222308)