[Molecular genetics of inherited chorioretinal dystrophy--strategy for identifying disease causing genes]

To review the strategies for identifying the causative genes of inherited chorioretinal diseases.

Three techniques, namely functional cloning, positional cloning, and positional candidate gene approach, have been used for this purpose. Our strategy for identifying the causative genes of inherited chorioretinal diseases is to clone retina-enriched genes, learn their chromosomal map position, and identify their expression in the retina.

In the past 10 years, one gene has been cloned by functional cloning, 9 genes by positional cloning, and 19 genes by the positional candidate gene approach. Our strategy has identified 3 novel genes expressed in the retina, but they have not been associated with chorioretinal diseases.

In the next century when the Human Genome Project is finished and the human genome has been sequenced completely, the positional candidate gene approach will become the predominant method of disease gene discovery. The future success of this method is predicated on increasingly dense mapping of the responsible genes by linkage analysis of multiple affected families with inherited chorioretinal diseases.