What is the definition of Leber Congenital Amaurosis?
Leber congenital amaurosis (LCA) is an eye disorder that primarily affects the retina. People with this condition typically have severe visual impairment beginning in infancy. Other features include photophobia, involuntary movements of the eyes (nystagmus), and extreme farsightedness. The pupils also do not react normally to light. Additionally, the cornea may be cone-shaped and abnormally thin (keratoconus). Franceschetti's oculo-digital sign is characteristic of Leber congenital amaurosis. This sign consists of poking, pressing, and rubbing the eyes with a knuckle or finger. Different subtypes have been described. The different subtypes are caused by mutations in different genes. Some of these subtypes are also distinguished by their patterns of vision loss and related eye abnormalities. Treatment includes correction farsightedness and use of low-vision aids when possible.
What are the alternative names for Leber Congenital Amaurosis?
- Congenital absence of the rods and cones
- Congenital retinal blindness
- Leber's amaurosis
- Leber's congenital tapetoretinal degeneration
- Leber's congenital tapetoretinal dysplasia
- Amaurosis congenita of Leber
What are the symptoms for Leber Congenital Amaurosis?
Leber congenital amaurosis (LCA) primarily affects the retina, the specialized tissue at the back of the eye that detects light and color. Beginning in infancy, people with LCA typically have severe visual impairment. This is most often non-progressive, but sometimes it very slowly worsens over time. Other vision problems associated with LCA include:
- Clouding of the lens of the eyes (cataract)
- Crossed eyes (strabismus)
- Enophthalmos (eye balls are dislocated backward)
- Abnormal retinal pigment
- Extreme farsightedness (hyperopia)
- Pupils that may not react normally to light; they may expand and contract more slowly than normal, or they may not respond to light at all
- Keratoconus, a condition in which the cornea is cone-shaped and abnormally thin, may also be present
A specific behavior called Franceschetti's oculodigital sign is characteristic of LCA. This behavior consists of poking, pressing, and rubbing the eyes with a knuckle or finger. It may possibly contribute to deep-set eyes and keratoconus in affected children.
In rare cases, delayed development, hearing loss, and intellectual disability have been reported in people with the features of LCA. However, it is unclear whether these people actually have LCA or another syndrome with similar signs and symptoms.