The genetics of childhood cataract

Human congenital cataract has a diverse aetiology. In the proportion of cas es where the cause is genetic, the disease shows wide phenotypic and geneti c heterogeneity. Over the past few years, much research has been devoted to mapping the genes that underlie the disorder. This has been helped by the extensive array of naturally occurring and genetically engineered mouse cat aract models and the abundance of human candidate genes. Most progress to d ate has been in the identification of genetic mutations causing autosomal d ominant congenital cataract where eight genes have been implicated in catar actogenesis. Overall there is good correlation between the genetic mutation s so far identified and the resulting lens phenotype but it is clear that m utations at more that one locus may give rise to similar forms of cataract. The identification of genes causing inherited forms of cataract will improv e our understanding of the mechanisms underlying cataractogenesis in childh ood and provide further insights into normal lens development and physiolog y. Perhaps more importantly, it is likely that some of the genes causing ea rly onset cataract will be implicated in age related cataract which remains the commonest cause of blindness in the world.