Leber Congenital Amaurosis (LCA)
Eye Conditions & Care | Eye Conditions | Leber Congenital Amaurosis (LCA)
Leber's Congenital Amaurosis is a degenerative disease that results in a severe loss of vision. This disease is thought to be caused by abnormal development of photoreceptor cells in the retina or the extremely premature degeneration of the retinal cells. Typically a baby with LCA will have very reduced vision at birth although the retina may appear normal when first examined. Within months, however, parents will usually notice nystagmus - an involuntary, rhythmical, repeated movement of the eyes. LCA varies greatly from relatively mild acuity (clarity of vision) problems (20/70) to no light perception.
Occasionally, LCA may be confused with other retinal problems such as Retinitis Pigmentosa. LCA is genetically passed through families, and both parents must be carriers. This is referred to as an autosomal recessive pattern of inheritance. Please see Inheritance Patterns for more information.
Children with LCA often have eyes that appear sunken or deep set. They may press on the eyes frequently; this is called oculo-digital reflex. Some children with LCA have cone-shaped corneas (Keratoconus) and cataracts that cause the corneas to become cloudy. By the time a child reaches adolescence, pigmentary changes occur in the retinal pigment epithelium (the supportive tissue underneath the retina). This is similar to changes that occur to the retina with Retinitis Pigmentosa. This occurs because the blood vessels in the retinas become narrow and constricted. Unlike Ushers Syndrome, where a progressive loss of vision is typical, vision loss in individuals with LCA usually remains stable through young adult life. Progression of vision loss later in life has not yet been clearly defined. Additionally, some individuals with LCA are very sensitive to light (photophobic). Children with some remaining vision are likely to be extremely farsighted as well.
In some cases, individuals with LCA also show central nervous system complications. They may be developmentally delayed, have seizure disorders, or motor impairments.
Research into the gene that causes LCA (RPE65) has reached the human clinical trial stage.