Down syndrome is a genetic condition caused by abnormal cell
division in the egg, sperm, or fertilized egg. This results in an extra or
irregular chromosome in some or all of the body's cells, causing varying levels
of intellectual disability and physical problems.
syndrome is also called trisomy 21, for the specific chromosome that has the
abnormality. A person with Down syndrome has three copies of chromosome 21. Normally, a person has two copies.
Down syndrome usually can be
detected during pregnancy or soon after birth. Chromosome (karyotype) tests and how a baby looks can help make a diagnosis.
Babies usually have distinctive facial characteristics, such as
upward-sloping eyes and a flattened nose. People with Down syndrome have an
increased risk of being born with or developing health problems. For example,
some babies with Down syndrome are born with heart, intestinal, ear, or
respiratory defects. These health conditions often lead to other problems, such
as respiratory infections, sleep apnea, or hearing problems. Other health
issues, such as vision trouble or problems with thyroid function, can also
Children with Down syndrome grow and develop more slowly
than other children. But most are able to attend school, play sports,
socialize, and enjoy active lifestyles. Unless their disabilities are severe,
adults with Down syndrome can care for most of their own needs. Many people
who have Down syndrome live into their 50s and some into their 60s or older.
July 20, 2011
Susan C. Kim, MD - Pediatrics & Louis Pellegrino, MD - Developmental Pediatrics
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