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Genetic Testing for Inherited Retinal Diseases
Recognizing Signs and Symptoms
The symptoms of an inherited retinal disease vary depending on which type a person has and how far it has progressed. Some conditions appear in infancy, while others are not noticed until adulthood. Knowing what to look for helps families seek evaluation sooner.
Leber congenital amaurosis is one of the earliest-presenting IRDs. Parents may notice that their infant does not fix their gaze on objects, does not follow movement with their eyes, or rubs their eyes frequently. This eye rubbing, known as the oculodigital sign, occurs because pressing on the eye stimulates remaining photoreceptor cells.
X-linked retinoschisis is typically diagnosed in males from early infancy through school age. Symptoms can include crossed eyes, abnormal eye movements, and reduced vision that may only be caught during a routine school vision screening.
Many IRDs develop gradually over years or even decades. Retinitis pigmentosa often begins with difficulty seeing in dim light or at night, a symptom sometimes called night blindness. Over time, the visual field narrows inward, creating a tunnel vision effect that slowly reduces peripheral sight.
Stargardt disease tends to appear in childhood or early adulthood and primarily affects central vision. A person may notice blurriness or distortion when reading, trouble recognizing faces, or a gradual change in color perception.
Any unexplained or progressive change in vision should be evaluated by a Retina Specialist. Symptoms that deserve prompt attention include increasing difficulty seeing at night, narrowing side vision, blurry or distorted central vision, and unusual sensitivity to light.
If a child shows signs of poor visual tracking, frequent eye rubbing, or abnormal eye movements, a thorough examination is important. The earlier an IRD is identified, the sooner families can access genetic testing and explore available treatments or clinical trials.
Diagnosing IRDs With Genetic Testing
Diagnosing an inherited retinal disease involves both a thorough clinical eye examination and, in most cases, genetic testing. These two steps work together to give patients and families the most complete picture possible. A clinical exam identifies the pattern of retinal damage, while genetic testing identifies the specific gene responsible.
The process typically begins with a comprehensive retinal evaluation by a Retina Specialist. This evaluation may include optical coherence tomography (OCT), a scan that produces detailed cross-section images of the retinal layers, and electroretinography (ERG), a test that measures the electrical activity of the retina's light-sensing cells.
Other imaging tools such as fundus photography, wide-field imaging, and fluorescein angiography may also be used to assess the extent and pattern of retinal damage. These tests help narrow down which condition may be present, but a clinical exam alone cannot identify the specific gene involved.
Genetic testing analyzes a person's DNA to look for mutations in genes associated with inherited retinal diseases. The DNA sample is typically collected through a simple blood draw or a saliva sample. The sample is sent to a specialized laboratory where the DNA is read and compared to a reference of the human genome to identify any meaningful differences.
Modern genetic testing uses a method called next-generation sequencing (NGS), which can read many sections of DNA at the same time and greatly improves the speed and accuracy of the analysis.
Several types of genetic tests are available, and the most appropriate one depends on each patient's clinical findings and family history.
- Targeted gene panel: Tests a set of genes known to cause inherited retinal diseases, often covering more than 250 IRD-associated genes
- Whole exome sequencing: Analyzes all protein-coding regions of the genome, going beyond standard panels to find mutations in less commonly tested genes
- Whole genome sequencing: The most comprehensive option, examining nearly all of a person's DNA including regions outside of protein-coding areas
Your Retina Specialist will help determine which approach makes the most sense based on your clinical picture.
Panel-based genetic testing identifies a causative gene mutation in approximately 60 to 70 percent of cases. This means that in some cases, a specific mutation is not found even though the condition is almost certainly genetic in origin.
An inconclusive result does not mean the disease is not inherited. It may mean the responsible mutation is in a region that current technology cannot fully analyze, or in a gene that has not yet been linked to retinal disease. As testing technology improves and new IRD genes are discovered, retesting in future years may yield a definitive result.
The Role of Genetic Counseling
Genetic counseling is a key part of the process for patients and families navigating an IRD diagnosis. It bridges the gap between a laboratory result and meaningful, actionable understanding. A genetic counselor is a healthcare professional trained specifically to interpret and explain genetic test results in the context of each family's unique situation.
A genetic counselor explains the inheritance pattern of the gene change that was found, what that means for other family members who may be at risk, and how the condition could potentially be passed to future children. This information helps families make informed decisions about testing other relatives, family planning, and long-term care.
Counseling is valuable both before testing, to set expectations and explain the process, and after testing, to help families understand what the results mean in practical terms.
Genetic counseling is available through academic medical centers, specialized eye care clinics, and increasingly through telemedicine services, which makes access easier for patients in more rural areas. A Retina Specialist can provide a referral to a genetic counselor with expertise in eye conditions and inherited retinal disease.
Treatment Options for IRDs
Treatment options for inherited retinal diseases depend entirely on the specific gene involved. While not every IRD has an approved therapy today, genetic testing is often the first step toward accessing the treatments that do exist, as well as clinical trials for conditions that are still in research stages.
Luxturna (voretigene neparvovec) was approved by the U.S. Food and Drug Administration as the first gene therapy for an inherited retinal disease. It delivers a working copy of the RPE65 gene directly into retinal cells and is designed for patients who have vision loss caused by mutations in both copies of the RPE65 gene.
Genetic testing is required to confirm RPE65 mutations before a patient can be considered for this treatment. Without a confirmed genetic diagnosis, eligibility cannot be established. This is one of the clearest examples of why genetic testing matters, even when no symptoms have yet appeared in all family members.
Numerous clinical trials are underway to develop gene therapies for other forms of inherited retinal disease, including conditions such as Stargardt disease, choroideremia, X-linked retinitis pigmentosa, and achromatopsia. Some trials use gene replacement approaches similar to Luxturna, while others are exploring more advanced gene editing technologies.
Patients with a confirmed genetic diagnosis are better positioned to determine whether they qualify for these studies. A Retina Specialist can help review whether any active trials align with a patient's specific mutation.
For IRDs that do not yet have an approved therapy, supportive care plays an important role in preserving quality of life. This includes regular retinal monitoring with imaging tools like OCT, the use of low vision aids such as magnifiers, orientation and mobility training, and assistive technology for reading and daily activities.
Protecting the eyes from excessive light exposure and maintaining overall health through regular follow-up care can help preserve remaining vision. A Retina Specialist may also discuss nutritional supplements that have been studied in certain retinal conditions, though no supplement has been proven to halt IRD progression.
Living With an Inherited Retinal Disease
A genetic diagnosis changes how patients and families think about the future. It opens doors to treatment eligibility and clinical trials, but it also calls for thoughtful planning and ongoing care. Understanding what to expect helps patients take a more active role in protecting their vision.
After a genetic diagnosis, regular follow-up with a Retina Specialist is important. Imaging tools such as OCT allow the specialist to track changes in retinal structure over time, detect any progression early, and adjust care as needed. The pace of vision change varies widely depending on the specific condition and gene involved, and knowing the mutation can help provide a more accurate outlook.
A confirmed genetic diagnosis gives families meaningful information for planning. Couples who know their carrier status can work with a genetic counselor to understand the likelihood of passing the condition to their children. Options such as preimplantation genetic testing during in vitro fertilization may be available and worth discussing.
A diagnosis can also help individuals plan practically for potential changes in vision by connecting with vocational rehabilitation services, adaptive technology training, and independent living programs before significant vision loss occurs.
The field of inherited retinal disease research is advancing at a meaningful pace. New genes are being identified, testing methods continue to improve, and additional therapies are moving through clinical trials. Patients with a confirmed diagnosis can register with clinical trial databases to stay aware of new opportunities.
Organizations such as the Foundation Fighting Blindness and the National Eye Institute offer up-to-date information on research progress, patient resources, and support services.
Frequently Asked Questions
These answers address common questions patients and families have after learning about genetic testing for inherited retinal diseases.
Yes, it is possible. A negative or inconclusive result reflects the state of testing technology and scientific knowledge at the time the test was performed. As researchers identify new IRD-associated genes and laboratory methods improve, mutations that earlier tests could not detect may become identifiable. If you received an inconclusive result in the past, it is worth discussing retesting with your Retina Specialist, particularly if several years have passed since your original test.
No eye procedures are required for the genetic test itself. The sample is collected through either a blood draw or a saliva sample, both of which are simple and minimally uncomfortable. The clinical eye examination that usually precedes testing may include pupil dilation, which temporarily causes light sensitivity and blurred near vision for a few hours afterward. Planning to have someone drive you home after a dilated exam is a good idea.
Not necessarily, and the answer depends on the inheritance pattern of the specific mutation. In autosomal recessive conditions, a child must receive a changed copy of the gene from both parents to develop the disease. If only one parent carries the mutation, the child may be a carrier but would not be affected. In autosomal dominant conditions, each child has roughly a 50 percent chance of inheriting the gene change. A genetic counselor can provide a personalized risk assessment based on your specific mutation and family history, which is far more informative than a general estimate.
As of now, Luxturna remains the only FDA-approved gene therapy for an inherited retinal disease. However, this does not mean treatment options are limited to a single condition. Research programs are actively studying therapies for multiple other IRDs, and some patients with non-RPE65 mutations may qualify for clinical trials. Your Retina Specialist can review your specific genetic diagnosis and help identify whether any active trials or expanded access programs may be relevant to your situation.
In many cases, yes. Because some IRDs are inherited in a recessive pattern, family members may carry a mutation without having any vision symptoms at all. Identifying carriers is important both for family planning decisions and because some conditions can begin causing subtle changes before a person notices any vision loss. Early testing in at-risk family members can support earlier monitoring and, in some cases, earlier access to treatment.
Schedule a Retinal Evaluation at Atlantic Retina Center
If you or a family member is experiencing unexplained vision changes or has a known family history of inherited retinal disease, our team is here to help. Atlantic Retina Center serves patients across the Eastern Shore of Maryland and central and southern Delaware with specialized vitreoretinal care focused exclusively on the retina, vitreous, and macula. Our fellowship-trained, board-certified Retina Specialists use advanced diagnostic imaging and work alongside genetic counseling services to give each patient a thorough and accurate diagnosis. We encourage you to reach out and schedule an evaluation so we can help you understand your vision and your options.