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Gene Therapy

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What is gene therapy?

The answer to this question - and much more - can be found on MedlinePlus, a service of the U.S. National Library of Medicine and the national Institutes of Health.

Gene therapy is an experimental technique that uses genes to treat or prevent disease. The most common form of gene therapy involves inserting a normal gene to replace an abnormal gene.  Other approaches include:

  • Swapping an abnormal gene for a normal one
  • Repairing an abnormal gene
  • Altering the degree to which a gene is turned on or off

Although there is much hope for gene therapy, it is still experimental.

I've heard there is a treatment available for Leber congenital amaurosis (LCA). Please tell me more.

There have been a number of compelling news reports recently, particularly this Wall Street Journal article.

The article begins with this statement: "A small but provocative study showed that a form of gene therapy significantly improved the vision of patients left legally blind by a rare genetic eye disease."

Needless to say this study, which recently took place at the Children's Hospital of Philadelphia, has generated a lot of excitement. "Researchers said the findings amount to an important advance toward medicine's ambitious but generally unrealized dream of replacing disease-causing mutant or missing genes with normal DNA to treat and cure debilitating illnesses."

The mere mention of the University of Iowa and Dr. Edwin Stone, a co-author of this study, has resulted in numerous inquiries from many people anxious to learn more. People living with vision loss, whether their own or that of a loved one, are beginning to feel hopeful, and for very good reason.

The results of this study are truly amazing. However, due to the number of inquiries, we feel it is important to point out that this study is on a particular inherited eye disease called Leber congenital amaurosis(LCA). Considered a form of Retinitis Pigmentosa or “RP”, LCA is a very specific disease caused by very specific genetic variations or “mutations”. The gene RPE65 is the focus of this particular study. And while there are currently no active (LCA) clinical trials occurring at the University of Iowa as one article erroneously mentioned, there is one being organized for 2010. The Carver Family Center for Macular Degeneration will conduct Phase III of this ongoing study.

What does this mean to the hopeful people currently inquiring about the progress of gene therapy to treat vision loss? Well, it means there is good reason to be optimistic for the future. Collectively speaking, “we” (physicians and scientists) are on the brink of offering genetic therapy to treat childhood blindness caused by Leber congenital amaurosis. In time, we hope to be able to treat a host of other currently incurable retinal disorders.

What can you do in the meantime? If you or someone you love is living with an inherited eye condition, you can investigate your options. Consult with your physician, preferably an ophthalmologist, to determine if there is a genetic test currently available appropriate for your diagnosis (see "Genetic Tests We Offer"). GeneTests.org is another reliable source for such information. Knowing the specific molecular genetic variation of your condition is an important first step. Not only is this information important in terms of potential gene therapy treatment in the future, but it can also be useful now. There are many eye conditions that can be “managed” via treatment or vision rehabilitation.

For additional information about the current study at Children’s Hospital of Philadelphia, please visit this site or contact Dr. Albert Maguire, MD via email.

For additional information about the University of Iowa and the future LCA RPE65 Phase III clinical trial being planned, please refer to this web site periodically. Updates will be posted as they become available.

Additional reading

I'm wondering if gene therapy might be an option for me?

Dear Doctor,

I am a 39 year old man with LCA. I have some “functional” vision. I am fortunate to be able to read very large print and can almost always make my way around safely and without incident. Almost. I haven’t let LCA slow me down. I have a fulfilling, productive and happy life. But I would be lying if I said that I don’t care about seeing the baseball when I watch a game.

I am hearing more and more about clinical trials and am wondering what the protocol is for being included. I am not 100% sure I would actually want to participate as I understand there is potential risk involved. I would have to give some serious thought to the prospect of losing what vision I do have, but I sure would appreciate being better informed about possible future options.

Thank you,
Sam R.

Dear Sam,
I appreciate your taking the time to write to me.

Do you have a molecular diagnosis yet? If not, that is something that you may wish to consider because gene replacement therapies require knowledge of the specific genetic abnormality in each patient.

I highly recommend you read through the information on our web site, including the FAQ section. If you have not yet received a genetic test to confirm your diagnosis but feel you should, the next step would be to share this information with your ophthalmologist.

I hope this information is helpful to you.

Best wishes,
Ed Stone

Articles of Interest:

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Retrieved Sat, 2018-12-15 17:04
Last modified Mon, 01/12/2009 - 20:44
www.carverlab.org/faqs/gene-therapy