Leber's congenital amaurosis (LCA) is a rare inherited retinal dystrophy characterized by vision loss, often from birth. LCA is the most severe form of all inherited retinal dystrophies, accounting for at least 5% of all such cases. It is also one of the main causes of blindness in children. The estimated birth prevalence of LCA is two to three per 100,000 births. There are at least 13 types of Leber congenital amaurosis. These types are distinguished by their genetic cause, patterns of vision loss, and related eye abnormalities.
Clinical diagnosis is based on clinical history of failure to develop reactions to visual stimuli, roving eye movements or nystagmus, sluggish pupillary responses and a normal, or less frequently an abnormal fundus on dilated fundoscopy. To date, no definitive treatment or cure for LCA exists.
Leber's congenital amaurosis is generally inherited in an autosomal recessive pattern, although some autosomal dominant families have been reported. At least 20 different genes involved in LCA have been identified. LCA type I is caused by mutations in the GUCY2D gene, located on chromosome 17p13.1. This gene is expressed in the photoreceptor cells, where it plays an essential role in normal vision.