Down syndrome is a set of
physical and mental traits caused by a
gene problem that happens before birth. Children who have
Down syndrome tend to have certain features, such as a flat face and a short
neck. They also have some degree of
intellectual disability. This
varies from person to person. But in most cases it is mild to moderate.
Down syndrome is a lifelong condition. But with care
and support, children who have Down syndrome can grow up to have healthy,
happy, productive lives.
Down syndrome is caused
by a problem with a baby's
chromosomes. Normally, a person has 46 chromosomes. But most
people with Down syndrome have 47 chromosomes. In rare cases, other chromosome
problems cause Down syndrome. Having extra or abnormal chromosomes changes the
way the brain and body develop.
Experts don't know the exact
cause, but some things increase the chance
that you'll have a baby with Down syndrome. These things are called risk factors.
Your risk of having a baby with Down syndrome is higher if:
- You are older when you get pregnant. Many doctors believe that the risk increases for women age 35 and older.
- You have a brother or
sister who has Down syndrome.
- You had another baby with Down syndrome.
If you've had a baby with Down syndrome and are planning another pregnancy, you may want to talk to your doctor about genetic counseling.
Most children with Down
- Distinctive facial features, such as a flat
face, small ears, slanting eyes, and a small mouth.
- A short neck
and short arms and legs.
- Low muscle tone and loose joints. Muscle tone
usually improves by late childhood.
- Below-average intelligence.
Many children with Down syndrome are also born with
heart, intestine, ear, or breathing problems. These health conditions often
lead to other problems, such as airway (respiratory) infections or hearing
loss. But most of these problems can be treated.
Your doctor may
suggest that you have tests during pregnancy to find out if your baby has Down
syndrome. You may decide to have:
- Screening tests, such as an ultrasound or a blood test during your first or second trimester. These can help show if the developing baby (fetus) is at
risk for Down syndrome. But these tests sometimes give
false-positive or false-negative results.
- Diagnostic tests, such as chorionic villus sampling or amniocentesis. These can show if a baby has Down syndrome. You may want to have these tests if you have abnormal results from a screening test
or if you are worried about Down syndrome.
Sometimes a baby is diagnosed after birth. A doctor
may have a good idea that a baby has Down syndrome based on the way the baby
looks and the results of a physical exam. To make sure, the baby's blood will
be tested. It may take 2 to 3 weeks to get the test results.