Transcript The Big 4: RP - Mississippi State University

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 nonsex-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
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 lightsensing 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.h
tm/printable
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

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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
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.