Retinitis Pigmentosa (RP) BJ LeJeune, CRC, CVRT Mississippi State University

Retinitis Pigmentosa (RP) RP refers to a group of inherited eye diseases that affect the retina. Retinitis pigmentosa causes the degeneration of photoreceptor cells in the retina, usually starting with the rods and progressing to the cones. Sometimes known as Rod-Cone Dystrophy or retinal Dystrophy As these cells degenerate and die, patients experience progressive vision loss.

Related inherited diseases Bardet-Biedl (Laurence-Moon) syndrome Best disease, Choroideremia, Gyrate-atrophy, Leber congenital amaurosis

Heredity and RP Retinitis pigmentosa is an inherited disease that has many different modes of inheritance. RP, with any inheritance pattern, may be either familial (multiple family members affected) or isolated (only one affected person). In the non-sex-linked, or autosomal, form, it can either be a dominant or recessive trait. In the sex-linked form, called x-linked recessive, it is a recessive trait. Autosomal dominant - 20% Autosomal recessive - 37% X-linked recessive - 4.5% Sporadic - 38.5%

Usher Syndrome About 3-6% of children who are Deaf or hard of hearing have RP. RP is a hereditary disease that usually affects people as youth or young adults and worsens over the decades of life. When combined with Deafness or hearing loss, the combination is known as Usher Syndrome.

The Eye

Photoreceptor Cells

Pigmented Retinal Tissue

Initial Symptoms of RP Night Blindness Reduced side vision or blind spots Clumsiness Discomfort in dark situations Difficulty transitioning from light to dark and dark to light Light sensitivity Communication Considerations: May need to move further ways Keep signs small in a contained space Contact sign to follow hand Difficult to see at night or in lighting situations that change.

Early stage of RP

More advanced RP

Tests for RP Electroretinogram (ERG) Measures the electrical response of the retina to flashes of light. An electrode is placed on the surface of a numbed eye and a reference electrode on the skin of the face. Can be done at any age, even as an infant, and the presence of RP can be detected before any visual symptoms appear.

Those at Risk for Usher Syndrome and RP RP is hereditary and comes in a number of hereditary types which impact both the onset and severity. Certain forms (US3) are found in families of Scandinavian dissent, especially those who are Finnish. RP is found among all races and more common in many closed societies including Cajuns, Native Americans, and Deaf cultures.

Types of Usher Syndrome Type 1 (US1): Born Deaf with a balance problem, and usually acquire initial stages of RP as children or youth. Type 2 (US2): Born with mild hearing loss, no balance problems, acquire RP about age 10-20. Hearing and vision both deteriorate rather slowly. Type 3 (US3): Born with hearing loss which deteriorates rapidly, normal balance, acquire RP in the teen years.

Treatment There is no cure for RP or US at this time although the Foundation Fighting Blindness (www.blindness.org) is leading research efforts to find a cure. Other major research is being done at the National Center for the Study and treatment of Usher Syndrome at Boy’s Town

Treatment Research While not a cure, certain doses of vitamin A have been found to slightly slow the progression of retinitis pigmentosa in some individuals. Identification of the genes that cause retinitis pigmentosa. It is now possible, in some families with X-linked RP or autosomal dominant retinitis pigmentosa, to perform a test on genetic material from blood and other cells to determine if members of an affected family have one of several Retinitis Pigmentosa genes.

Vitamin A For people with Usher Syndrome and Retinitis Pigmentosa a daily dose of 15000 International units of Vitamin A Palmitate (only) has been shown to slow the degeneration of the cone ERG. A blood test must be taken to ascertain liver function and Vitamin A levels in the blood BEFORE taking this treatment.

Promising Research Nutrition (Vitamin A) www.blindness.org Medications ("Vision Aid") www.retinitispigmentosa.com Retinal Transplants www.eyesight.org Bio-Technology Gene Therapies and Stem Cell Research Herbal Therapies http://focusnewsletter.org

Retinal Transplants 1. The cells in the transplant must stay alive for a long time, preferably for the life of the recipient 2.Those cells must have, and maintain, the light-sensing activities of normal, healthy retina cells 3.Those cells must transmit electric or electrochemical signals to the brain, which the brain can interpret as the experience of vision.

Gene Therapy and Stem Cell Research National Eye Institute www.nei.nih.gov National Center on the Study and Treatment of US www.Boystownhostpital.org Fighting Blindness www.blindness.org National Eye Institute funds research for retinal diseases including RP, and MD FFB researchers have discovered over 100 genes that can contain mutations leading to Retinitis Pigmentosa Information is available on their web site at www.blindness.org

Bio-Technological Solutions

Bio-Tech: BrainPort http://science. howstuffworks. com/brainport

The RP Personality Bright, intelligent, motivated Masters at “Bluffing” Optimistic and confident on the outside, fearful on the inside Class clown, clumsiness becomes a joke

RP Personality Continued Over-achievers, often trying to test or prove themselves Often very socially outgoing in the day time, but rarely go out at night. Reluctant to accept “blindness” (i.e. cane, Braille) Often drive when it is no longer safe.

Implications for Employment Vision Loss is progressive Difficulty adjusting to various lighting conditions Balance issues for some people with US Really good at faking it! Reluctant to admit they can’t see something – safety issues Need more help than they admit.

Prevention Routine eye exams Exercise regularly Monitor Blood Pressure Don’t Smoke Eat colorful foods (Veggies Fighting Vision Loss) Wear protective eye wear (100% UVA and UVB protection) AND a wide brimmed hat Consult your doctor before taking vitamin supplements Eating plenty of fruits and vegetables also keeps your eyes in good shape. You may have learned that the vitamin A in carrots aids night vision. Other fruits and vegetables help prevent two common aging-related eye diseases - cataract and macular degeneration - which afflict millions of Americans over age sixty-five. Cataract is the gradual clouding of the eye's lens, a disk of protein that focuses light on the light-sensitive retina. Macular degeneration is caused by cumulative damage to the macula, the center of the retina. It starts as a blurred spot in the center of what you see. As the degeneration spreads, vision shrinks. Free radicals generated by sunlight, cigarette smoke, air pollution, infection, and metabolism cause much of this damage. Dark green leafy vegetables contain two pigments, lutein and zeaxanthin, that accumulate in the eye. These two appear to be able to snuff out free radicals before they can harm the eye's sensitive tissues.(12) In general, a diet rich in fruits, vegetables, and whole grains appears to reduce the chances of developing cataract or macular degeneration. (13-15)

What else can a consumer do? Genetic Testing and Counseling Participate in Clinical Research National Eye Institute www.nei.nih.gov National Center on the Study and Treatment of US www.Boystownhostpital.org Fighting Blindness www.blindness.org Report visual history to researchers to help them track the impact of the disease.