Crosses of heterozygous HCII+/- animals in the mixed 129/SvJ x C57Bl/6 genetic background produced 154 offspring at the expected Mendelian ratio. Thus, homozygous HCII deficiency does not produce a lethal phenotype in utero.
Three month old HCII-/- mouse (left) with HCII+/+ littermate (right)