Likewise, addition of heterozygous deletion of Csnk2b (Runx2+/Osx;Csnk2b+/Osx mice) or Hausp (Runx2+/Osx;Hausp+/Osx mice) results in more severe CCD phenotypes in Runx2+/Osx mice (Fig. 6p). This evidence concerns the gene RUNX2 and cleidocranial dysplasia 1.