By lmg on March 23rd, 2010
Facts About Usher Syndrome
Usher syndrome is a genetic condition that effects hearing, sight and balance.
Usher syndrome is an inherited condition in which a child is born deaf
or with hearing loss, and progressively loses their vision due to a
group of hereditary diseases of the retina, known as Retinitis
Pigmentosa, or RP. With RP, the retina degenerates slowly and loses its
ability to send pictures to the brain. For Usher Syndrome to be present,
both conditions must be present and they must be caused by a single
gene. Usher syndrome effects approximately 3 to 6 percent of all deaf
children and it is believed to affect an equal number of children who
are hard of hearing. Usher syndrome, itself, is more than one genetic
condition. It is estimated that 1 in 10,000 adults have Usher syndrome
of one type or another, and approximately 4 out of every 100,000 babies
born have Usher syndrome.
Usher syndrome is an inherited disease. This means that it is passed
from parent to child. In order for a child to be born with Usher
syndrome, both parents must be carriers of the gene. If only one parent
is a carrier, the child will not have the disease, however; if both
parents carry the gene, there is a 25% chance that the child will have
the disease, a 50% chance that the child will be a carrier of the
disease, and a 25% chance that the child will neither have the disease
nor be a carrier.
There are three types of Usher syndrome. Types 1 and 2 are most common
in the United States. It is estimated that 90 to 95 percent of all cases
of Usher syndrome in the United States are either type 1 or type 2.
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who are affected with type 1 Usher syndrome are deaf at birth and have
severe problems with balance. These children experience little to no
benefit from the use of hearing aids. Night blindness is present in
infancy or early childhood. By late childhood or early teens, blind
spots in the person's vision begin to appear. By early adulthood, the
person is legally blind. Children with type 1 Usher syndrome are
generally slow to sit without support and rarely walk independently
before the age of 18 months.
Those who are affected with type 2 Usher syndrome are born with moderate
to severe hearing loss and normal balance. Night blindness begins in
late childhood or early teenage years. By late teenage or early
adulthood years, blind spots begin to appear in the person's vision. The
person becomes legally blind in early to mid adulthood years. Children
affected with type 2 Usher syndrome generally benefit from the use of
hearing aids and have the ability to communicate orally. Vision problems
progress more slowly than in type 1 Usher syndrome and the onset of
Retinitis Pigmentosa is often not apparent until teenage years.
Those affected with type 3 Usher syndrome are born with normal hearing
at birth. They progressively lose their hearing in their childhood or
early teenage years. Hearing loss, once it begins, tends to progress
rapidly, over a 10 to 15 year period, until hearing loss is profound.
Balance problems vary in severity, but often progresses with age. The
rate at which hearing and vision are lost varies from person to person,
even within families where more than one person is affected. Night
blindness normally begins during puberty. By the late teen to early
adulthood age, blind spots begin to appear in the person's vision. By
mid-adulthood years, the person may become legally blind.
Usher syndrome effects hearing, vision and balance. Because of this,
diagnosis of the disorder includes testing of all three. Visual field
tests to determine the person's peripheral vision, an ERG, or
electroretinogram is performed to measure the electrical responses of
the light-sensitive cells within the eye, and an examination of the
retina and other parts in the back of the eye to determine any
abnormalities are all tests done to hearing test is performed to determine how loud sounds need to be in a
specific frequency before the person hears them. This helps to monitor
and determine any hearing loss. To test the person's balance, an ENG, or
electronystagmogram is performed to measure any involuntary eye
There is currently no cure for Usher syndrome. Early detection is best
for helping those affected learn how to cope with this disorder. There
are many educational programs available to help. Typical treatment will
include hearing aids, cochlear implants, assisted listening devices
and/or other communication methods, including the teaching of sign
language. Other services are available to help teach the affected person
how to communicate with others to the best of their ability, retain
mobility, live as independently as possible, read by using Braille, as
well as other low-vision services and auditory training.
Some ophthalmologists believe that a high dose of Vitamin A palmitate
may slow the progression of vision loss due to Retinitis Pigmentosa.
Because of this, some ophthalmologists will recommend a daily supplement
of Vitamin A palmitate at the dosage of 15,000 IU daily. Those who use
this form of treatment should be careful not to exceed the daily dose.
It is important to note that this treatment is not recommended for those
with type 1 Usher syndrome. Some guidelines are in place for those who
use this type of treatment. These guidelines include not substituting
Vitamin A palmitate with a beta-carotene supplement, not taking more
than the recommended dosage, women who are using this treatment should
stop treatment three months before trying to conceive a child due to the
increased risk of birth defects, and women who are pregnant should stop
this treatment due to the risk of birth defects. In addition to these
guidelines, a person using this treatment should not consume more than
400 IU of Vitamin E each day.
Usher disease, although not fatal, can be very debilitating for those
who are affected. Early diagnosis along with education and training can
help those individuals live a more productive and independent life. The
sooner the disorder is diagnosed, the sooner treatment can begin. If you
suspect that your child may be affected by Usher syndrome, the best
thing you can do is seek a medical opinion.
Sources for this article include: