Jan 4, 2013

Getting the Right Diagnosis for a Retinal Disease

Science Education

Definitive diagnoses for inherited retinal diseases don’t always come easy, even for the patients of the most knowledgeable doctors.

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Definitive diagnoses for inherited retinal diseases don’t always come easy, even for the patients of the most knowledgeable doctors. Comments posted to this blog over the past year are a testament to that fact. Many readers are understandably frustrated by a doctor’s inability to determine exactly what retinal condition is affecting them or loved ones.

While getting an accurate diagnosis can be challenging, trying to do so is important because it may enable an affected person to: 1) determine which clinical trials and emerging treatments may be appropriate; 2) better understand how vision may change over time; and 3) figure out if family members may be at risk for the disease.

So why can diagnoses be tough to come by? First and foremost, most eye doctors don’t see many patients affected by inherited retinal diseases, because the conditions are rare. They simply don’t have familiarity with them, even if they learned about them in medical school and during their residency training.

Another major reason diagnoses are tough is that some conditions can look the same to even a well-trained retinal specialist. For example, cone-rod dystrophy affects the macula, the central region of the retina, much in the same way that Stargardt disease does. X-linked retinitis pigmentosa (XLRP) and choroideremia can look similar in appearance. Sometimes it isn’t clear upon examination whether a young child has retinitis pigmentosa or a form of Leber congenital amaurosis.

Also, diseases don’t always behave the way experts expect them to. XLRP is a great example of this phenomenon. According to textbooks, XLRP only affects men; females are unaffected carriers. But in recent years, researchers have found that a surprising number of women have vision loss, sometimes severe, from XLRP.

Despite these challenges, there are things you can do to improve your chances of getting an accurate diagnosis:

Visit a Clinician at a Retinal Research Center
Academic research institutions are where most experts in inherited retinal diseases practice, and FFB funds many of them. Known as “clinician-researchers,” they have the most knowledge and the best tools to make diagnoses.

These centers are located in many major cities in the United States, Europe and Asia. While it can be financially and logistically difficult for some patients to visit these centers regularly, even one visit can make a world of difference in understanding a disease.

Contact the Foundation at 1-800-683-5555 or info@FightingBlindness.org to find the research center most convenient for you. We also maintain a list of privately practicing retinal doctors who are knowledgeable about inherited retinal degenerations.

Get Genetically Tested
Finding the disease-causing gene is the key to making a definitive diagnosis. If you find the genetic defect, you have the answer. Furthermore, finding the gene can position you for clinical trials of emerging treatments.

Of course, the genetic-testing process can be a real bear. That’s because only about 45 percent of the genes that cause these diseases are known, and the discovery of new genes is a research effort that can take many years. It isn’t like getting your cholesterol checked at your local doctor’s office or lab — you won’t get an answer right away, and sometimes you won’t get an answer for years until the gene is identified during research.

Also, it is best to contact a specific research center, and potentially its genetic counselor, to get a genetic test. The Foundation has online genetic testing resources, and the company InformedDNA offers fee-based, genetic counseling services over the phone for people with inherited retinal diseases.

Be Persistent and Tenacious
I can’t say enough how important it is to advocate for one’s self in getting answers to questions about a diagnosis or genetic test results. While people might not always get the answers they want — e.g., “We can’t find your gene” — they should get an answer. At the end of the day, they must make the follow-up calls to get the information to better understand a condition and how to deal with it.

For those who do jump through all these hoops and can’t get a definite diagnosis, there is good news. The Foundation funds several emerging treatments — including drugs, gene therapies and stem cell treatments — that are designed to work for people with a wide range of diagnoses.

Many of these potential therapies are funded through our Translational Research Acceleration Program and positioned to move into human studies within the next few years.

Finally, the Foundation is funding a number of outstanding researchers, who, thanks to advancing technology, are continually improving their ability to find disease-causing genes and make diagnoses.

Clearly, there continue to be formidable challenges for doctors, researchers and patients, but we are getting more answers to inherited retinal diseases every day.