The allele contains a 10 bp deletion (AAGATGATGA) in intron 5 (NM_001289458), and occurs beginning +1990 from end of exon 5 and -3632 from the beginning of exon 6 (NM_001289458). A 1.863 kb floxed Neo selection casette was introduced in intron 5 at chr5:16,569,650 (GRCm38/mm10) in the original line. Cre-mediated recombination removed the selection cassette.