The insertion of NorCOMM cassette pNTARU created a deletion of size 331bp between positions 40120962-40121293 of Chromosome 9 (Build GRCm39). This deletion results in the removal of functionally critical exon(s). The cassette is composed of an F3 site followed by a universal inverse PCR primer site and a splice acceptor lacZ-neomycin phosphotransferase fusion (beta-geo) sequence. This is followed by a PhiC31 attP site and a puromycin sequence that is not active unless a promoter is inserted by PhiC31 at the attP site. The cassette is finished with an FRT site. Variations of this allele can be made using PhiC31 docking and subsequent cloning (Nagy et al., 2009. Methods Mol. Biol. 530:365-78).