The invention relates to a pharmaceutical composition comprising a recombinant adeno-associated virus (r AAV) vector carrying a nucleic acid sequence encoding a functional gene under the control of regulatory sequences which express the product of said gene in the retinal cells, for use in a method for preventing or treating an inherited retinal degenerative disorder associated with mutations in said gene, wherein the pharmaceutical composition is administered during the same operative period by at least one subretinal injection in each quadrant of retina of the patient in need thereof and wherein said quadrants consist of infero-temporal retina, supero-temporal retina, infero-nasal retina and supero-nasal retina.

The present invention relates to the prevention and/or treatment of retinal dystrophyin a patient, including Leber congenital amaurosis (LCA).

A method for treating an ocular disorder characterized by the defect or absence of a normal gene in the ocular cells of a human or animal subject involves administering to the subject by subretinal injection an effective amount of a recombinant adeno-associated virus carrying a nucleic acid sequence encoding the normal gene under the control of a promoter sequence which expresses the product of the gene in the ocular cells. The ocular cells are preferably retinal pigment epithelial (RPE) cells, and the gene is preferably an RPE-specific gene, e.g., RPE65. The promoter is one that can express the gene product in the RPE cells. Compositions for subretinal administration are useful in this method.

Methods for assaying function and/or activity and/or potency of isomerohydrolase proteins are provided.

A system for an ocular gene therapy is provided. The system includes one or more optimized transgenes. The one or more optimized transgenes include pAAV.CMV.CodOpt.RPE65 and pAAV.CMV.Kozak.RPE65. The optimized transgenes pAAV.CMV.CodOpt.RPE65 and pAAV.CMV.Kozak.RPE65 have shown to exhibit enhanced RPE65 gene expression when compared to wild type RPE65 gene transfer in suitable models. These optimized genes may enhance therapeutic response during LCA2 gene therapy. The present invention also provides a process for preparing the optimized transgene for an ocular gene therapy.

Methods for assaying function and/or activity and/or potency of isomerohydrolase proteins are provided.