General Condition Information
- Hyperornithine with gyrate deficiency
- It is unknown how many babies are born with this rare condition each year in the United States.
What is Gyrate Atrophy of the Choroid and Retina
Gyrate atrophy of the choroid and retina is an inherited (genetic) condition that prevents the breakdown of a substance in the blood called ornithine. Ornithine is an amino acid, one of the building blocks of protein.
Ornithine aminotransferase is an enzyme that helps break down ornithine. Ornithine aminotransferase helps balance amino acids so they can correctly produce proteins.
Without enough working ornithine aminotransferase enzyme, your baby will have trouble breaking down ornithine. High amounts of ornithine can damage your baby’s eyes and other organs. Left untreated, this damage leads to the signs and symptoms of the condition.
Newborn Screening and Follow-Up
Newborn screening for gyrate atrophy of the choroid and retina requires collecting a small amount of blood from your baby’s heel. To learn more about this process, visit the Blood Spot Screening page.
Screening measures how much ornithine is in your baby’s blood. Babies with high levels of ornithine might have gyrate atrophy of the choroid and retina.
If your baby’s blood spot screening result for gyrate atrophy of the choroid and retina is out-of-range, your baby’s health care provider will contact you. Together, you will discuss next steps and follow-up plans.
An out-of-range screening result does not mean that your baby definitely has the condition. It does mean that your baby needs more follow-up testing. To learn more about screening results, visit the Blood Spot Screening Results page.
Your baby may need the following tests after an out-of-range screening result:
- Blood and urine tests
- Genetic testing using a blood sample
- Special eye exams
You should complete any recommended follow-up testing as soon as possible. Babies with this condition can develop serious vision problems in childhood if they are not diagnosed and treated quickly.
False-positive newborn screening results for this condition can happen.
Newborn screening helps babies lead healthier lives. If your baby has an out-of-range result, follow up with your health care provider quickly. It is important to follow their instructions. Your baby may need to get treatment right away, even if they are not showing signs or symptoms. In some cases, your baby’s health care provider may decide it is best to watch (monitor) your baby to decide next steps. Careful monitoring and early treatment will help your baby stay as healthy as possible.
The signs of gyrate atrophy of the choroid and retina usually don’t begin until childhood. In rare cases, newborns may have some symptoms.
Signs of the condition may include the following:
- Nearsightedness (myopia)
- Night blindness
- Loss of side (peripheral) vision
- Clouding of the eyes (cataracts)
A change in the OAT gene triggers this condition. This gene supports production of the enzyme ornithine aminotransferase, which breaks down ornithine.
Without a working OAT gene, the body cannot break down ornithine. As a result, ornithine and related substances can build up and damage the eyes and other organs.
- Gyrate atrophy of the choroid and retina is an autosomal recessive condition. Babies inherit the condition when each parent passes down a nonworking OAT gene to their baby. Only babies with two nonworking OAT genes—one from the mom and one from the dad—have this condition.
- People with one working copy and one nonworking copy of the OAT gene are called carriers.
- Carriers do not have or develop the condition. However, they may pass down a nonworking copy of the gene to their children.
- If two parents are carriers of a nonworking copy of the OAT gene, they have a 1 in 4 chance of having a child with gyrate atrophy of the choroid and retina.
- Carriers for gyrate atrophy of the choroid and retina often do not know they are carriers before having a child with the condition. In most cases, families have no history of the condition until the birth of a child with gyrate atrophy of the choroid and retina.
- Parents who already have a child with gyrate atrophy of the choroid and retina still have a 1 in 4 chance of having another child with gyrate atrophy of the choroid and retina. This 1 in 4 chance stays the same for all future children.
- Genetic counselors and medical geneticists can help families learn about this condition and the chance of having children with it. Visit the National Society of Genetic Counselors to find a genetic counselor and the American College of Medical Genetics and Genomics to find a medical geneticist.
Treatment and Management
It is important to talk to your health care provider about which treatment(s) are best for your baby. The goal of treatment is to prevent the health problems caused by this condition.
Treatments may include the following:
- Diet low in certain proteins
- Vitamins and other supplements
- Vision aids, like eyeglasses
Children who receive early and ongoing treatment for gyrate atrophy of the choroid and retina can lead healthier lives.