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$Unique_ID{BRK04340}
$Pretitle{}
$Title{X-linked Juvenile Retinoschisis}
$Subject{X-linked Juvenile Retinoschisis RS Juvenile Retinoschisis X-linked
Retinoschisis Familial Foveal Retinoschisis Macular Degeneration }
$Volume{}
$Log{}
Copyright (C) 1991 National Organization for Rare Disorders, Inc.
797:
X-linked Juvenile Retinoschisis
** IMPORTANT **
It is possible that the main title of the article (X-linked Juvenile
Retinoschisis) is not the name you expected. Please check the SYNONYM
listing to find the alternate names and disorder subdivisions covered by this
article.
Synonyms
RS
Juvenile Retinoschisis
X-linked Retinoschisis
Information on the following disorders can be found in the Related
Disorders section of this report:
Familial Foveal Retinoschisis
Macular Degeneration
General Discussion
** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only. It should not be used for diagnostic or treatment
purposes. If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.
X-linked Juvenile Retinoschisis (RS) is a genetic disorder affecting
males. Major symptoms may include poor eyesight and degeneration of the
retina. The retina consists of membrane layers in the eye that receive
visual images after passing through the lens. It is composed of supportive
and protective structures, nervous system components and layers including
"rods" and "cones". RS is due to splitting of the retina which in turn
causes slow, progressive loss of parts of the fields of vision corresponding
to the areas of the retina which have become split. Often, RS is associated
with the development of cysts (sac-like blisters) in the retina.
Symptoms
Symptoms of X-linked Juvenile Retinoschisis (RS) may include poor eyesight,
detachment of all or part of the retina from the rest of the eye, and
eventually complete retinal atrophy (wasting away) with hardening of the
choroid (the membrane between the white part of the eye and the retina).
The patient may develop cysts in the macula (an oval area of the retina)
and other areas of the retina. The cysts lead to splits within the retina.
The cystic manifestations may also appear in other family members. Bleeding
within the eye may occur.
Problems with vision are usually mild up until the age of 40 or 50, after
which the condition may slowly worsen.
Causes
X-linked Juvenile Retinoschisis (RS) is inherited as an X-linked recessive
trait. Human traits, including the classic genetic diseases, are the product
of the interaction of two genes, one received from the father and one from
the mother.
X-linked recessive disorders are conditions which are coded on the X
chromosome. Females have two X chromosomes, but males have one X chromosome
and one Y chromosome. Therefore, in females, disease traits on the X
chromosome can be masked by the normal gene on the other X chromosome. Since
males only have one X chromosome, if they inherit a gene for a disease
present on the X, it will be expressed. Men with X-linked disorders transmit
the gene to all their daughters, who are carriers, but never to their sons.
Women who are carriers of an X-linked disorder have a fifty percent risk of
transmitting the carrier condition to their daughters, and a fifty percent
risk of transmitting the disease to their sons.
Affected Population
X-linked Juvenile Retinoschisis (RS) is a rare disorder present at birth.
The disorder affects males. Men of Finnish heritage are affected more often
than those of other heritages. Until the age of 40 or 50, visual handicap is
usually mild.
Related Disorders
Symptoms of the following disorders can be similar to those of X-linked
Juvenile Retinoschisis (RS).
Familial Foveal Retinoschisis is another type of Juvenile Retinoschisis
which involves splitting of tissue within the fovea (the center of the macula
and the area of clearest vision) of the retina. It is very similar to X-
linked Juvenile RS, but the changes in the retina are not as severe. A
completely blind area (scotoma), with a sharp edge in the area where
splitting occurs, is evident in the patient's visual field. Foveal RS can
also occur in patients with X-linked Juvenile RS. (For more information on
this disorder, choose "retinoschisis" as your search term in the Rare Disease
Database).
Macular Degeneration (MD) is characterized by a gradual decrease of
vision. It is inherited as a dominant trait. MD can be a static condition
for many years, but then becomes slowly progressive with age. Central vision
is impaired or absent in MD while peripheral vision remains normal. A vision
disturbance in which shapes seem distorted or changing (metamorphopsia) can
occur. An area of depressed vision within the visual field surrounded by an
area of normal vision (central scotoma) is also symptomatic of this disorder.
Polymorphic Macular Degeneration (PMD) is a dominant hereditary vision
disorder which includes Best Disease and Sorsby Disease. PMD usually affects
the macular region in both eyes. In Sorsby Disease swelling (edema),
hemorrhage, and cyst formation are noted. The cysts may vary in size and
appearance. The cystic manifestations may also appear in other family
members. In advanced stages considerable atrophy occurs. In Best Disease,
changes in the macular region, as well as other areas of the eye, may be
noted before visual impairment occurs. The macular area may show a yellow
mass resembling the yolk of an egg. This lesion may possibly be present at
birth. Deep irregular pigmentation inside the eye may develop later. (For
more information on these disorders, choose "Macular Degeneration" as your
search term in the Rare Disease Database).
Therapies: Standard
Diagnosis of X-linked Juvenile Retinoschisis (RS) can be made by an
ophthalmologist through various tests:
Measuring visual acuity with the Snellen chart, the patient is asked to
look through a pinhole to determine where on the retina a lesion may exist.
Ultrasonography or ultrasound may show abnormalities when a hemorrhage
has occurred in the eye.
A recording of the electrical impulses emitted by the retina in response
to light stimulus (electroretinogram; ERG) can be made. ERG's can indicate
abnormalities of the retina.
A Visual Evoked Response (VER) measures slow electric potentials from the
brain cortex in response to light stimulation. The VER depends on the
integrity of the entire visual system from the cornea to the occipital part
of the brain's cortex. The VER can detect a malfunction of the macular
portion of the retina which controls central vision.
A photographic picture made with an ophthalmoscope of the back portion of
the inside of the eyeball (fundus) is another way to gather information about
the retina.
When bleeding occurs within the eyeball, keeping the eye still helps to
reduce damage. Later, treatment with laser or cold (cryotherapy) can be
applied to close off the damaged area of the retina. It is imperative to
avoid jarring the head or inflicting injury to the eye to slow down the
degenerative process of RS.
Genetic counseling may be of benefit for patients with X-linked Juvenile
Retinoschisis and their families. Other treatment is symptomatic and
supportive.
Therapies: Investigational
Sulfur Hexafluoride is an experimental medical device for treatment of
patients with detached retinas. For information about clinical trials being
conducted, please contact:
Airco Welding Products
575 Mountain Ave.
Murray Hill, NY 07974
This disease entry is based upon medical information available through
June 1991. Since NORD's resources are limited, it is not possible to keep
every entry in the Rare Disease Database completely current and accurate.
Please check with the agencies listed in the Resources section for the most
current information about this disorder.
Resources
For more information on X-Linked Juvenile Retinoschisis, please contact:
National Organization for Rare Disorders (NORD)
P.O. Box 8923
New Fairfield, CT 06812-1783
(203) 746-6518
NIH/National Eye Institute
9000 Rockville Pike
Bethesda, MD 20892
(301) 496-5248
Association for Macular Disease, Inc.
210 East 64th Street
New York, NY 10021
(212) 605-3719
For genetic information and genetic counseling referrals:
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
(914) 428-7100
Alliance of Genetic Support Groups
35 Wisconsin Circle, Suite 440
Chevy Chase, MD 20815
(800) 336-GENE
(301) 652-5553
References
MENDELIAN INHERITANCE IN MAN, 8th Ed.: Victor A. McKusick; Johns Hopkins
University Press, 1986. Pp. 1173, 1373, 1375.
AUTOSOMAL JUVENILE RETINOSCHISIS WITHOUT FOVEAL RETINOSCHISIS. S. Hara
and K. Yamaguchi; Br J Ophthalmol (June 1989; issue 73 (6)). Pp. 470-473.
LINKAGE RELATIONSHIPS AND GENE ORDER AROUND THE LOCUS FOR X-LINKED
RETINOSCHISIS. T. Alitalo, et al.; Am J Hum Genet (Oct 1988; issue 43 (4)).
Pp. 476-483.
USE OF LINKED DNA PROBES FOR CARRIER DETECTION AND DIAGNOSIS OF X-LINKED
JUVENILE RETINOSCHISIS. N. Dahl and U. Pettersson; Arch Ophthalmol (Oct
1988; issue 106 (10)). Pp. 1414-1416.