The gene was disrupted by a gene trap insertion within intron 23 and resulted in a hypomorphic mutation. The gene trap contains a beta-galactosidase/neomycin reporter gene with a ribosomal reentry site (IRES) followed by a poly(A) tail. Genomic DNA PCR confirmed the insertion of the gene trap and localized it to 3.308 kb downstream of exon 24. (J:212182)