Leber Congenital Amaurosis.

Leber congenital amaurosis (LCA) is a part of the spectrum of early-onset retinal dystrophy (EORD). It usually presents in the first few years of life, most often before the age of 1 year. The prevalence is about 1:80,000. Also known as congenital retinitis pigmentosa (RP), patients have wandering nystagmus, with reduced vision from birth. The fundus is almost normal to start with. Later, pigmentary disturbances develop. The best corrected visual acuity (BCVA) ranges from no light perception (in nearly one third of cases) to no better than 20/400, often with a hyperopic refraction (≥5.0D). Patients have absent pupillary reflex and some of them have keratoconus (CRB1 and AIPL1). Oculodigital reflex (eye rubbing or poking) is a common association. Electroretinography (ERG) responses are almost undetectable. Patients may have normal intelligence, but some studies suggest that as many as 20% of children with LCA without associated anomalies develop intellectual disability. Patients with GUCY2D mutations have a stable clinical course; those with RPE65 mutations show a period of limited improvement followed by progressive deterioration; and those with AIPL1, CRB1, CEP290, and NMNAT1 mutations show gradual progression over several decades.