Leber congenital amaurosis (LCA) is a group of inherited retinal diseases characterized by severe impairment vision or blindness at birth. Some retinal experts consider LCA to be a severe form of retinitis pigmentosa (RP). The condition is caused by degeneration and/or dysfunction of photoreceptors, the cells in the retina that make vision possible. Photoreceptors capture light, converting it to electrical signals which are sent to the back of the brain to create the images we see. Mutations in one of more than two dozen genes can cause LCA.
Leber Congenital Amaurosis (LCA)
Often within an affected infant’s first few months of life, parents notice a lack of visual responsiveness and roving eye movements, known as nystagmus. Eye examinations of infants with LCA sometimes reveal normal-appearing retinas. In other cases, several abnormalities are observed. Regardless, an electroretinogram (ERG), which measures retinal function, detects little if any activity in the retina. ERG tests are often essential to establishing a diagnosis of LCA. A genetic test can often provide a definitive diagnosis.
Many children with LCA habitually press their eyes with their fists or fingers. This habitual pressing on the eyes is known clinically as oculodigital reflex. The eyes of individuals with LCA can also appear sunken or deep set. Keratoconus (cone shape to the front of the eye) and cataracts (clouding of the lens through which light passes) can occur with the disease.
In some cases, other body systems (e.g., kidneys) can be affected by the genetic defects that cause LCA.
LCA is almost always passed down through the autosomal recessive pattern of inheritance. In this type of inheritance, both parents, called carriers, have one mutated copy of the gene and one normal gene. They are unaffected carriers of LCA. Each of their children has a 25 percent chance of inheriting the two LCA gene copies (one from each parent) needed to cause the disorder.
Living with the Disease
There are many services and accommodative and assistive resources available to people and families with LCA. Visit the Foundation’s Living and Thriving pages to learn about many of these resources. A low vision specialist can help recommend the resources that are right for you.
More information on managing LCA is in the Newly Diagnosed section of this Web site.
Genetic testing is available for LCA, and helps with attaining an accurate diagnosis. A patient and family with a genetic diagnosis are in a better position to understand which emerging treatment approaches and clinical trials are most appropriate for them.
In December 2017, the biotech Spark Therapeutics obtained U.S. Food and Drug Administration approval for LUXTURNA™, an RPE65 gene therapy that has improved vision in children and young adults with RPE65 mutations. Early funding from the Foundation helped make this treatment possible. Treatments for forms of LCA caused by other mutated genes are in the development pipeline.