What is Retinitis Pigmentosa?
Retinitis pigmentosa (RP) is a group of inherited disorders in which photoreceptors (rods and cones) are progressively lost, with a gradual reduction in vision.
What are the symptoms?
Typically, early symptoms are problems seeing in dim light, reduced peripheral vision, or difficulty adjusting when going from a brightly lit area to a dimly lit area. The constriction of peripheral vision can lead to eventual loss of central vision late in the course of the disease. However, the presentation, severity and the age at which symptoms are first noticed varies greatly. Although many sources of information use the worst case scenario, in fact, some patients with RP retain useful vision throughout life. In addition, optical aids can greatly improve or prolong the use of vision such as magnifiers, closed-circuit television, and high-intensity, wide-beam flashlights. Diagnosis of RP by an ophthalmologist is made based on a number of symptoms. These include characteristic features in the fundus on an eye examination, and documentation of progressive loss in photoreceptor function by electroretinography (ERG) and visual field testing.
Is RP an inherited disease?
Yes; the mode of inheritance of RP is determined by family history. Many different genes cause RP and not all have been discovered at this time. RP can be inherited in an autosomal dominant, autosomal recessive, or X-linked manner. X-linked RP can be either recessive, affecting males only, or dominant, affecting both males and females; females are always more mildly affected. Genetic counseling depends on an accurate diagnosis, determination of the mode of inheritance in each family, and results of molecular genetic testing.
Is there a genetic test available?
At this time DNA testing is available for some of the genes most commonly causing RP and research screening for new mutations or RP genes continues. A genetic diagnosis can: confirm the clinical diagnosis, help predict how the disease will progress which in turn guides the treatment strategy, identify the risk of disease in children, and determine if relatives are carriers for a potentially disease causing mutation.
How can I order a genetic test for Retinitis Pigmentosa?
The John and Marcia Carver Nonprofit Genetic Testing Laboratory currently has a clinical genetic test available for Autosomal Dominant RP. For more information, follow this link. Testing for Autosomal Recessive RP is in development.
Is there a clinical trial available for this particular condition?
Research regarding the eye and blinding eye diseases is ongoing and the answer to this question might change on any given day. Thankfully there are resources available today to assist anyone interested in monitoring progress.
Where can I learn more about Retinitis Pigmentosa?
GeneTests is a publicly funded web site that provides medical genetics information. While primarily targeted to physicians, researchers and other healthcare providers, patients and their families interested in a reliable resource for their own research will find this up-to-date comprehensive web site an invaluable tool. See Retinitis Pigmentosa as found on GeneTests.org
The Genetic and Rare Diseases Information Center (GARD), a collaborative effort of two agencies of the National Institutes of Health: The Office of Rare Diseases Research (ORDR) and the National Human Genome Research Institute (NHGRI), is another most excellent resource.
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If you have any specific questions about Retinitis Pigmentosa, please consult your personal physician.
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