REGIONALLY RESTRICTED DEVELOPMENTAL DEFECTS RESULTING FROM TARGETED DISRUPTION OF THE MOUSE HOMEOBOX GENE HOX-1.5

Gene targeting in mouse embryo-derived stem cells has been used to disrupt the homeobox gene hox-1.5. Mice heterozygous at the hox-1.5 locus appear normal, whereas hox-1.5-/hox-1.5- mice die at or shortly after birth. These homozygotes are athymic, aparathyroid, have reduced thyroid and submaxillary tissue and exhibit a wide range of throat abnormalities. In addition, they often feature defects of the heart and arteries as well as craniofacial abnormalities. These deficiencies are remarkably similar to the pathology of the human congenital disorder DiGeorge's syndrome.