What is Down Syndrome?

Down syndrome is set of mental and physical symptoms that result from having an extra copy of Chromosome 21.

Normally, a fertilized egg has 23 pairs of chromosomes. In most people with Down syndrome, there is an extra copy of Chromosome 21 (also called trisomy 21 because there are three copies of this chromosome instead of two), which changes the body’s and brain’s normal development.

(For more information on chromosomes, see Cells 10

Syndrome of 'Down Syndrome':

In addition to the characteristic physical features and decreased mental abilities, other health problems frequently are seen in people with Down syndrome. These include:

• Hearing deficits
• Heart problems
• Intestinal abnormalities
• Eye problems
• Low levels of thyroid hormone
• Skeletal problems such as joint instability
• Poor weight gain in infants

People with Down syndrome develop leukemia more often than those without the disorder, and are at increased risk of infections, problems with the immune system, skin disorders and seizures.

Infants with Down syndrome usually develop more slowly than other children of the same age, although a wide variation is seen. Language development is typically much slower, as is motor development. For example, while most toddlers walk between 12 and 14 months of age, toddlers with Down syndrome walk between 15 and 36 months.

Who is at risk for Down syndrome?:

The chance of having a baby with Down syndrome increases as a woman gets older—from about 1 in 1,250 for a woman who gets pregnant at age 25, to about 1 in 100 for a woman who gets pregnant at age 40. But, most babies with Down syndrome are born to women under age 35 because more younger women have babies.

Because the chances of having a baby with Down syndrome increase with the age of the mother, many health care providers recommend that women over age 35 have prenatal testing for the condition. Testing the baby before it is born to see if he or she is likely to have Down syndrome allows parents and families to prepare for the baby’s special needs.

Parents who have already have a baby with Down syndrome or who have abnormalities in their own chromosome 21 are also at higher risk for having a baby with Down Syndrome.

Once the baby is born, a blood test can confirm whether the baby has Down syndrome.

Treatment of 'Down Syndrome:

There is no treatment to reverse the genetic abnormality that causes Down syndrome. However, many of the associated medical and developmental conditions can be addressed, enhancing the person's quality of life, improving developmental possibilities and increasing his or her life expectancy.

Many health-care professionals may be involved in assessing and planning the course of treatment for a child with Down syndrome. Surgery may be required for cardiac or gastrointestinal abnormalities.

Physical therapy and integrated special-education services help children with Down syndrome to make the most of their abilities and reach their potential. Children with Down syndrome usually respond very well to sensory stimulation, exercises to help their muscle control, and activities to assist their cognitive development. School helps children with Down syndrome to learn social, academic and physical skills that may allow them to attain a very high level of functioning and independence.

Prevention of 'Down Syndrome':

There is no way to prevent the chromosome abnormality that causes Down syndrome. However, the chance of having a child with Down syndrome increases as the age of the mother increases. Older mothers usually are offered additional screening tests to detect Down syndrome in the fetus. Some researchers have suggested that an older father also increases the risk.

Parents who already have a child with Down syndrome are more likely to have another child with the same problem in future pregnancies. Genetic testing can help to quantify the risk.