Common molecular pathways for patterning of the body axis, limbs, central nervous system, and face during embryonic...

Many congenital anomalies affecting the face are known to appear as syndromes or associations, in combination with other defects. Often, these involve the limbs, eyes, central nervous system, and body axis. A general, and understandable, tendency among clinical researchers has been to seek a single cell type or definable embryologic process on which to ascribe the etiologic basis for such associations. The possibility of a gene, or group of genes, under coordinate control has not received much attention until recently. With the advent of recombinant DNA technology and the current explosion in basic research on the molecular bases of embryonic development, however, several possibilities are beginning to emerge. Here, I will list a few genes whose expression during development suggests that the molecules they encode are used as part of a coordinate molecular pathway, and that they play a role in the development of systems that often appear together in congenital associations or syndromes.