Learning about Retinitis Pigmentosa – Genome

Learning About Retinitis Pigmentosa What is retinitis pigmentosa?

Retinitis pigmentosa (RP) is the name given to a group of inherited eye diseases that affect the retina (the light-sensitive part of the eye). RP causes the breakdown of photoreceptor cells (cells in the retina that detect light). Photoreceptor cells capture and process light helping us to see. As these cells breakdown and die, patients experience progressive vision loss.

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As the disease progresses and more rod cells breakdown, patients lose their peripheral vision (tunnel vision). Individuals with RP often experience a ring of vision loss in their periphery, but retain clear central vision. Others report the sensation of tunnel vision, as though they see the world through a straw. Many patients with retinitis pigmentosa retain a small degree of central vision throughout their life.

Other forms of RP, sometimes called cone-rod dystrophy, first affect central vision. Patients first experience a loss of central vision that cannot be corrected with glasses or contact lenses. With the loss of cone cells also comes disturbances in color perception. As the disease progresses, rod cells degenerate causing night blindness and peripheral vision.

Symptoms of RP are most often recognized in children, adolescents and young adults, with progression of the disease continuing throughout the individual's life. The pattern and degree of visual loss are variable.

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Retinitis pigmentosa is an inherited disorder, and therefore not caused by injury, infection or any other external or environmental factors. People suffering from RP are born with the disorder already programmed into their cells. Doctors can see the first signs of retinitis pigmentosa in affected children as early as age 10. Research suggests that several different types of gene mutations (changes in genes) can send faulty messages to the retinal cells which leads to their progressive degeneration. In most cases, the disorder is linked to a recessive gene, a gene that must be inherited from both parents in order to cause the disease. But dominant genes and genes on the X chromosome also have been linked to retinitis pigmentosa. In these cases, only one parent has passed the disease gene. In some cases, a new mutation causes the disease to occur in a person who does not have a family history of the disease. The disorder also can show up as part of other syndromes, such as Bassen-Kornzweig disease or Kearns-Sayre syndrome.

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There is no known cure for retinitis pigmentosa. However, there are few treatment options such as light avoidance and/or the use of low-vision aids to slow down the progression of RP. Some practitioners also consider vitamin A as a possible treatment option to slow down the progression of RP. Research suggests taking high doses of vitamin A (15,000 IU/day) may slow progression a little in some people, but the results are not strong. Taking too much vitamin A can be toxic and the effects of vitamin A on the disease is relatively weak. More research must be conducted before this is a widely accepted form of therapy.

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Learning about Retinitis Pigmentosa - Genome