MGI:1933196Mice homozygous for a gene trap allele show embryonic growth retardation, reduced cell proliferation, increased neural tube apoptosis, and death by E11.5. Mice homozygous for a knock-out allele show complete embryonic lethality prior to organogenesis. In vitro, blastocysts hatch from the zona pellucida but form irregular outgrowths with a few adherent trophoblast giant cells after 3 days in culture.