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Article Provided by The ARC of Georgia
Fact
Sheet
Down Syndrome is a chromosomal abnormality, caused in most cases by an
extra copy of chromosome 21. It is the most common single cause of
human birth defects, with an occurrence in 1
out of every 660 births.
Children with Down syndrome have a widely recognized characteristic
appearance. The head may be smaller than normal. Prominent facial
features include a flattened nose and upward slanting eyes. The inner
corner of the eyes may have a rounded fold of skin (epicanthal fold)
rather than coming to a point. The hands are short and broad with
short fingers and often have a single crease in the palm. Normal
growth and development is slower than usual and most affected children
do not reach average adult height.
Mosaic Down Syndrome
When a person has more than one type of chromosomal makeup, that is
called mosaicism, like the mosaic style of art in which a picture is
made up of different colors of tiles. In Down syndrome, mosaicism
means that some cells of the body have trisomy 21
and some have the
typical number of chromosomes.
At the present time, there is not much research on the similarities
and differences between simple trisomy 21 and mosaic trisomy 21. For
more information, see
Down Syndrome
– Health issues
Helpful Information:
Following are some health problems that can occur in people with Down
Syndrome (DS). Because trisomy 21 affects many aspects of development, your
child will probably be checked for them. But it does not mean that
your child will be affected with all of the problems.
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Vision
problems: Children with Down syndrome may also have vision impairments
such as congenital cataracts, crossed-eyes or strabismus,
nearsightedness, farsightedness, inflammation of the eyelids (blepharitis),
and conjunctivitis. These conditions can be very successfully
addressed both medically and with educational modifications and low
vision adaptations.
-
Hearing
loss: A large percentage of children with Down syndrome have hearing
deficits. They may have sensorineural loss, conductive loss related to
ear infections, or both. Small ear canals are associated with this
syndrome.
-
Sinusitis:
Also is frequently a problem
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Cardiac
abnormalities
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Gastrointestinal obstruction (imperforate anus and similar problems)
-
Esophageal
atresia or duodenal atresia
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Blocked
airways during sleep (one third of patients)
-
Atlantoaxial Instability (AAI): Instability
of the back bones at the top of the neck. From
increased mobility at the division between the first and second
cervical vertebrae (atlantoaxial joint). This may be due to
abnormalities of the ligaments that maintain the integrity of the
articulation, bony abnormalities of the cervical vertebrae, or both.
Approximately 15% of youth with DS have AAI. Almost all are
asymptomatic. AAI is diagnosed with a cervical spine X-ray.
Having this cervical spine problem may limit
participation in sports.
-
Early-onset Alzheimer’s disease: Estimates vary, but a reasonable
conclusion is that 25 percent or more of individuals with Down
syndrome over age 35 show clinical signs and symptoms of Alzheimer's.
The percentage increases with age. In the general population,
Alzheimer's disease does not usually develop before age 50, and the
highest incidence (in people over age 65) is between five and 10
percent. The incidence of Alzheimer's disease in the Down syndrome
population is estimated to be three to five times greater than in the
general population.
Your
doctor may do tests on your child, including, but
not limited to:
-
Chromosome studies (demonstrates three
copies of 21st chromosome in 94% of cases)
-
Chest
x-ray (to determine presence of cardiac abnormalities)
-
Echocardiogram (to determine nature of cardiac abnormality)
-
Gastrointestinal x-ray (to show obstruction if symptoms are
suggestive)
Resources:
Down
Syndrome Association of Atlanta
National Down Syndrome Society
National
Association for Down Syndrome
National Down Syndrome Congress
Down Syndrome
Health issues
Down Syndrome Online
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The impact of a
disability can always be lessened to some degree by early intervention. |
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