Leber Congenital Amaurosis — Genotyping Required for Possible Inclusion in a Clinical Trial
The genetic heterogeneity of LCA no longer needs to be demonstrated. Indeed, the six already known disease-causing genes and the two additional LCA loci only account for 45% of all patients. To this tremendous genetic heterogeneity corresponds an almost equivalent physiopathological heterogeneity and to a minor extent a clinical variability. Therefore, the identification of LCA-causing genes and subsequent genotyping is an obligatory prerequisite to classify patients and include them in clinical trials. For this reason, we have collected several consanguineous multiplex families affected with LCA and performed a genome-wide search for homozygosity. Three distinct chromosomal regions, different from the 8 already known LCA loci, have been identified for three unrelated families. The candidate genes lying in these regions are currently analyzed. On the other hand, very recently, encouraging therapeutic trials have been performed in order to propose gene therapy to the RPE65 subgroup. Nevertheless, to date in Europe, the major LCA gene is GUCY2D. It is why it seems important to us to develop a therapeutic approach for this group. A murine retinal explant model of pharmacological-induced GUCY2D deficiency is currently developed in our group. This model will be of primary importance to screen different drugs for their ability to slow, stop or reverse the phenotype.
KeywordsRetinitis Pigmentosa Visual Cycle Retinitis Pigmentosa GTPase Regulator Kinase Homology Domain Single Heterozygote
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