People with leber congenital amaurosis (LCA) often have severe vision problems or are unable to see at all because of a genetic disorder that affects their retinas. People with LCA are born with the condition, and symptoms are often recognized soon after birth.
Keep reading to learn more about LCA disorder causes, symptoms, diagnosis, and treatment options.
What Is Leber Congenital Amaurosis?
Leber congenital amaurosis happens when certain types of gene mutations affect the cells that make up your child’s retinas. LCA can be caused by many different gene mutations but is usually a recessive disorder, meaning that both parents have to carry the mutated genes to have a child with LCA. If both parents are carriers, they have a 25% chance of having a child with LCA, which makes it very rare. LCA can happen to both male and female babies and affects 2 to 3 out of every 100,000 babies born each year.
Despite its rarity, LCA is the leading cause of genetic blindness in children. While not every child born with LCA disorder will be completely blind, LCA causes severe vision problems because it affects rod and cone cells in your child’s retinas. Rods and cones are types of photoreceptor cells. They react to light that enters the retina and send messages to the brain, which in turn creates an image.
If those cells don’t work properly, they aren’t able to effectively send signals to the brain. Cone cells help you see colors and other details, while rod cells help your brain process shades of gray and are important for being able to see at night or in dark places.
What Are Leber Congenital Amaurosis Symptoms?
Leber congenital amaurosis can be recognized shortly after birth. Babies born with LCA will not respond as well to light or other visual stimulation. Many children with LCA will rub or poke at their eyes often, sometimes causing their eyes to look more deep-set or even sunken.
Leber congenital amaurosis symptoms are not always the same for each person with the disorder. The severity of symptoms also varies.
Some of the most common LCA symptoms include:
- Inability to see or severe visual impairment and farsightedness
- Crossed eyes (strabismus)
- Sensitivity to light (photophobia)
- Involuntary eye movements (nystagmus)
- Cone-shaped corneas (keratoconus)
- Abnormally colored retinas
- Abnormally shaped optic discs
Some people with LCA might also have:
- Encephalocele (a type of neural tube defect)
- Weakness or paralysis in one arm or leg, or on one side of the face or body
- Low muscle tone
Less commonly, LCA can also cause developmental delays, learning disabilities, and hearing problems.
How Is Leber Congenital Amaurosis Diagnosed?
Children with leber congenital amaurosis will often have retinas that appear normal during routine eye exams, so more specialized tests are needed to make a diagnosis.
If your child shows symptoms of LCA, your doctor will order an electroretinography (ERG) test. An ERG uses special eyedrops to dilate the eye and a hard-lensed contact to help measure how your child’s eye responds to light. Doctors can diagnose LCA based on how much electrical activity passes through the retina as it reacts to different lights. Children with LCA have very low or no electrical activity in their retinas.
You might also be asked to have genetic counseling or certain tests to find out which genes are affected and to confirm a more exact LCA diagnosis.
What Are Leber Congenital Amaurosis Treatment Options?
Children born with LCA who have low vision will generally develop more severe eyesight problems as they get older. Many people with LCA will be completely blind by the time they're 30 or 40 years old. The main goal of leber congenital amaurosis treatment has traditionally been to offer support and relief for symptoms, as there is currently no cure.
Doctors might prescribe different types of electrical or optical visual aids to help improve vision for people with limited eyesight. Physical therapies and occupational training might also be recommended to help people with LCA adapt and function at work or school.
In recent years, ongoing clinical trials and gene therapy have proven effective at treating children and adults with certain types of LCA. The FDA approved a gene therapy called Luxturna in 2017 for people with the RPE65 gene mutation, which accounts for about 6% of LCA cases.
How Does Leber Congenital Amaurosis Gene Therapy Work?
Current and ongoing research has shown that gene therapy for certain forms of leber congenital amaurosis can help improve vision problems caused by the disorder. Gene therapy has been used for many different conditions and works by inserting new DNA into the mutated cells. This can potentially allow the cell to use the nondefective gene and function more normally.
One type of gene therapy that has shown to be particularly effective during clinical trials for people with LCA caused by the RPE65 gene mutation involves a type of adeno-associated viral vector (AAV). This type of gene therapy uses modified viruses combined with special strains of DNA to get inside the affected cells and help improve vision. AAV gene therapies are unique in that they can improve cell function at every stage of the cell cycle.
More research and development will be needed, but studies have shown that AAV gene therapy using normal RPE65 genes is safe and effective at improving eyesight for most people with LCA caused by RPE65 mutations. In one study, people who had gene therapy for LCA had their vision tested before and after receiving treatment. After gene therapy, people with LCA were able to see better overall and even at nighttime or in dark conditions.
Living With Leber Congenital Amaurosis
If you or your child has LCA, be sure to talk with your doctor about treatment options and support programs that can help improve both your vision and your quality of life at work or in school.
If you’re an adult with LCA who is struggling financially, ask your health care provider for resources that can help you qualify for income assistance or find employment.
While there is currently no cure for LCA, early management and occupational therapy can help people adapt and live their lives more normally. Ongoing research and clinical trials show promising results for the future of gene therapy and other LCA treatments.