An overview of developmental genetics in mammals

Ocular malformations and developmental genes

New insights into the pathogenesis of ocular malformations came with the discovery of transcription factors that determine the fate of cells in the developing eye. Several malformations have been matched to individual developmental genes that share conserved DNA sequences such as the homeobox. These disease/gene matches include the oculorenal syndrome and PAX2; aniridia and PAX6; Rieger syndrome and RIEG1/PITX2; cyclopia and Sonic hedgehog; cone-rod dystrophy, Leber's congenital amaurosis and CRX; and recessive septooptic dysplasia and HESX1. Gene mapping and mutation analysis have allowed a more accurate and meaningful classification of genetically heterogeneous diseases such as the anterior segment dysgenesis syndromes. This paper reviews current information on the genetics of ocular malformations.

Developmental expression of a novel murine homeobox gene (Chx10): evidence for roles in determination of the neuroretina and inner nuclear layer

Few potential regulatory proteins of vertebrate retinal development have been identified. We describe a 39 kDa murine polypeptide (Chx10) with a homeodomain 82% identical to that of the nematode protein ceh-10. In the developing mouse, the Chx10 transcript is expressed throughout the anterior optic vesicle and all neuroblasts of the optic cup. In the mature retina, the Chx10 protein is restricted to the inner nuclear layer, in which its expression decreases from the outer to the inner margin. Chx10 transcripts are also detected in regions of the developing thalamus, hindbrain, and ventral spinal cord. The data suggest that Chx10 plays critical roles in the formation of the neuroretina and in the development and maintenance of the inner nuclear layer.