How can I go to school if I can’t see anything?
— 16-year-old with Stargardt disease
Diagnosis
Misdiagnosis of Stargardt disease is common.
Typically, the onset of Stargardt disease happens in childhood; some people first begin noticing symptoms at a young age or in early adulthood. This is considered early–onset Stargardt disease. Early-onset forms of the disease may have a faster progression. Individuals diagnosed at a later age (45 or older) have a late-onset form of the condition, which may progress more slowly.
For early–onset cases, initial diagnosis can be difficult because the retina may appear normal, lacking the characteristic appearance of lesions seen in the retina of people with Stargardt. Early signs in patients with Stargardt may appear as bright “flecks” when assessed by fundus autofluorescence (FAF) imaging. Consequently, younger people with Stargardt are frequently misdiagnosed with other eye conditions or simply prescribed eyeglasses.
What I saw yesterday,
I cannot see today.
— 19–year–old with Stargardt disease
The following types of exams and/or tests can detect Stargardt disease for diagnosis:
Fundus autofluorescence (FAF) imaging is performed using a specialized camera called a fundus camera. During the exam, the patient’s eyes are dilated with eye drops to allow for a better view of the back of the eye, specifically the retina. The autofluorescence filter on the camera allows it to detect the natural fluorescence emitted by certain molecules, like lipofuscin. FAF imaging enables eye specialists to identify the characteristic signs associated with Stargardt disease, such as the bright flecks that denote lesions caused by lipofuscin, and areas of atrophy (black areas representing dead tissue).
Optical coherence tomography (OCT) is a non-invasive imaging test used to visualize the layers of the retina and measure their thickness. The images acquired by OCT can provide valuable information about the structure and health of the retina, as well as track disease progression by detecting abnormalities (such as thinning or thickening) or structural changes in the retinal pigment epithelium (RPE) and photoreceptor layers.
Electroretinography (ERG) is a procedure that assesses the retina’s responses in different types of light. During an ERG test, the patient’s eyes are dilated with eye drops and electrodes are placed on the surface of the eye or on the skin around the eye. The electrodes record electrical signals from the retina when it is exposed to flashes of light of varying intensities and wavelengths. These responses provide information about the function of the retina and can possibly identify abnormalities in the electrical responses of the retina.
Dilated eye exam, where eye drops are administered to dilate the pupil, allowing a physician to assess the retina for the presence of bright flecks or well-defined black areas associated with atrophy.
Genetic testing on blood samples detects the ABCA4 mutation and confirms Stargardt disease diagnosis.
In the case of inherited retinal diseases (IRDs) like Stargardt disease, genetic testing can identify the specific gene mutation responsible for the condition.
This knowledge can:
1
Help establish or verify a
diagnosis
2
Provide a better
understanding of how the
disease may progress
3
Assist family members
in understanding their genetic risks
and help you make informed
decisions about family planning
4
Open the door to potential
treatment options
5
Provide a pathway for
participation in certain
clinical trials
For more information on available clinical trials, visit ClinicalTrials.gov
Along with other diagnostic testing and examinations, genetic testing helps provide your eye care team with a more comprehensive picture of your condition, allowing them to tailor treatments if available and recommendations to your unique needs.
Genetic testing is also often a prerequisite for participating in clinical trials, making it an important step in exploring new therapies.
Genetics 101: Understanding Autosomal Recessive Inheritance
Stargardt disease cannot be fully diagnosed without a genetic test.
While clinical examinations and imaging can reveal signs of Stargardt disease, genetic testing is essential for identifying the specific gene variation that contributes to the condition. This precise diagnosis helps guide treatment, evaluate family risk, and open pathways to clinical trials.
The information below is designed to help you better understand how Stargardt disease is inherited and why genetic testing is a critical step in managing the condition.
| Stargardt disease is often passed down through families in a pattern called autosomal recessive inheritance. |
- Two Copies Needed: A person must inherit two altered (mutated) copies of a specific gene—one from each parent—to develop Stargardt disease
- Carriers: Parents who each carry one altered gene copy typically do not show symptoms; they are known as carriers
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- A 25% chance (1 in 4) of inheriting two altered genes (one from each parent) and developing the condition
- A 50% chance (1 in 2) of inheriting one altered gene, becoming a carrier like the parents, but not developing symptoms
- A 25% chance (1 in 4) of inheriting two normal genes, meaning they neither have the condition nor are carriers
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Important Considerations for Genetic Testing
Genetic testing requires careful thought.
Results may not always yield immediate answers and can sometimes lead to uncertainty or emotional challenges for patients and their families.
Even though tests can provide valuable insights, they may not always identify the disease-causing gene. In these cases, a genetic counselor is essential for interpreting results, addressing uncertainty, and recommending next steps.
This may include additional testing, monitoring, or exploring clinical trial opportunities. Even when a causal gene is found, genetic counselors help explain what the results mean for treatment options, family planning, and long-term care decisions.
- Clinical Examination: A thorough evaluation by a retina specialist or an inherited retinal disease specialist is a critical first step. This helps narrow the scope of testing and improves accuracy while reducing costs
- Medical Consultation: A meeting with an eye care provider or genetic counselor to determine if testing is appropriate
- Informed Consent: A discussion to help you understand the benefits, limitations, and possible outcomes of the test
- Sample Collection: Providing a biological sample, such as blood or saliva, which is then analyzed in a specialized lab
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- Healthcare Providers: Specialists can often order genetic tests or provide referrals
- Genetic Counselors: These professionals offer insights into the processes, interpret results, and advise on next steps
- Specialized Clinics: Certain facilities focus on genetic conditions and provide both testing and counseling services
- Clinical Trials: Participation in research studies exploring new therapies often requires genetic testing
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Specialists in Inherited Retinal Diseases: What’s the Difference?
While both retina specialists and inherited retinal disease (IRD) specialists focus on eye health, their areas of expertise overlap but are not identical.
A retina specialist is an ophthalmologist—a medical doctor specializing in eye and vision care—who has undergone additional training to diagnose and treat diseases of the retina, macula, and vitreous. They often manage conditions like age-related macular degeneration and diabetic retinopathy. Some retina specialists may also incorporate management of genetic retinal conditions into their practice, depending on their experience and focus.
An IRD specialist is also an ophthalmologist who often focuses on genetic retinal conditions, such as Stargardt disease. These specialists may integrate genetic testing and counseling into their care to provide more personalized treatment for inherited conditions. However, not all IRD specialists incorporate genetic counseling, and there is variability in how these specialists approach patient care.
If you are looking to find a provider, Foundation Fighting Blindness provides a helpful resource here: FightingBlindness.org/
retinal-specialists
The costs of genetic testing and counseling can vary, and many insurance providers may offer coverage.
It’s important to discuss your potential coverage with your insurance company, genetic counselor, or eye care professional before proceeding.
Results may take several months, and in some cases, re-testing at a later time may be recommended.
Utilize “My Retina Tracker”:
Foundation Fighting Blindness’ sponsored registry for individuals and families affected by inherited retinal degenerative diseases. This resource provides valuable data for research and clinical trials while helping you connect with others in the community.
www.MyRetinaTracker.org
It is essential to discuss the potential implications of genetic testing with a healthcare provider or genetic counselor to ensure you are making the best choice for your health and future.
Vitamin A is an essential component of the visual cycle. In this process, vitamin A in the form of 11-cis-retinal is transported from the retinal pigment epithelium (RPE) to the adjacent photoreceptor cells they support. In the initial stage of the visual cycle, 11-cis-retinal binds with opsins (light sensitive proteins) and initiates the conversion of light stimuli into the electrical signals the brain interprets as vision. During this process, 11-cis-retinal is converted to all-trans-retinal, releasing vitamin A byproducts. All-trans-retinal is then transported to the RPE to be recycled back into 11-cis-retinal, ready to be utilized in future visual cycles.
The vitamin A byproducts that are produced as a result of the visual cycle are usually cleared by ABCA4, preventing the accumulation of byproducts in RPE cells.
Due to the inability of ABCA4 to transport material outside the photoreceptor cell, an excess of built-up vitamin A byproducts can stick together, forming dimers (two proteins bound together). Vitamin A dimers accumulate in RPE cells in lipofuscin deposits, a toxic buildup of lipids, proteins, and cellular debris. Lipofuscin deposits compromise the function and survival of RPE cells, leading to the deterioration of RPE cells and the photoreceptor cells they support. These macular lesions progressively grow over time and may lead to significant vision loss.
