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This abstract is assigned to session BOG: Belgisch Oftalmologisch Gezelschap

Title	Leber congenital amaurosis
Abstract Nr.	320

Purpose	Leber congenital amaurosis (LCA) is a genetically and clinically heterogenous hereditary retinal disorder causing profound visual loss, nystagmus, poorly reactive pupils and a markedly diminished electroretinogram (ERG) due to the loss of photoreceptor function. Theodor Leber first described the condition in 1869 as a severe form of retinitis pigmentosa presenting in infancy or early childhood, with the absence of photoreceptor function.
Methods	An overview of the current status of knowledge regarding phenotypes and genotypes will be presented.
Results	The molecular genetics of LCA has been studied rather intensely over the last decade. All twelve genes so far identified, GUCY2D, RPE65, CRX, AIPL1, CRB1, RPGRIP1, RDH12, IMPDH1, TULP1, CEP290, LCA5 & SPATA7 have different functions in the retina. Together they account for 60 to 70% of all patients. Two additional loci have also been identified, on chromosomes 14q24 (LCA 3) and 1p36 (LCA 9) in consanguineous families. It is also becoming increasingly clear that particular phenotypes can sometimes be attributed to specific genotypes. In addition, successful gene therapy of RPE65-related LCA in a Briard dog model of the disease has now been translated into treatment trials in humans in both the UK and the USA, with initial success.
Conclusion	With the discovery of 12 genes to date which account for a majority of LCA patients, and the identification of genotype-phenotype correlations, knowledge about the pathogenesis of LCA is increasing rapidly. In addition, the advent of gene therapy in humans with RPE65-related LCA, makes this an exciting era for patients, parents and genetic ophthalmologists alike.

Author 1

Last name	LEROY
Initials	BP
Department	Dept of Ophthalmology & Ctr for Medical Genetics, Ghent University Hospital
City	Ghent