Leber congenital amaurosis

Leber congenital amaurosis is a group of inherited retinal disorders that cause severe visual impairment or blindness from birth or early infancy, often with markedly reduced retinal responses.

Photoreceptor: A retinal cell that detects light and converts it into electrical signals. These light-sensitive cells are impaired or lost in many forms of the disorder.
Electroretinography: A test that measures the electrical responses of the retina to flashes of light. Responses are often markedly reduced or undetectable in affected infants.
Voretigene neparvovec: A gene therapy that delivers a functional RPE65 gene to retinal cells. It can improve vision in eligible patients with biallelic RPE65-associated retinal disease.
Early-onset severe retinal dystrophy: An inherited retinal disease with severe visual impairment beginning in early childhood, often overlapping clinically with Leber congenital amaurosis. The labels can describe a continuum of severity and age at onset rather than cleanly separate disorders.
Retinal pigment epithelium: A layer of cells that supports photoreceptors and processes components of the visual cycle. Variants affecting this layer can disrupt retinal support and cause the disorder.
Fundus examination: An examination of the interior surface of the eye, including the retina and optic disc. The retina may look relatively normal early, despite severe visual dysfunction.
Gene therapy: Treatment that introduces, replaces, or modifies genetic material to address disease. The RPE65 treatment established a gene-replacement approach for one molecular subtype.
Achromatopsia: An inherited cone disorder causing impaired color vision, light sensitivity, and reduced visual acuity from infancy. It can begin early, but its cone-specific features differ from the broader retinal dysfunction here.
Visual cycle: The biochemical pathway that regenerates light-sensitive retinal in photoreceptors. Defects in visual-cycle genes can leave photoreceptors unable to respond normally to light.
Genetic heterogeneity: The phenomenon in which variants in different genes can cause similar or related disorders. Many different genes can produce the Leber congenital amaurosis phenotype.

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