Down syndrome is the genetic condition resulting when a baby is born with three, rather than the usual two, copies of chromosome 21. Because there are three copies of chromosome 21, Down syndrome is also called Trisomy 21. Instead of 46 chromosomes, a person with Trisomy 21 has 47. This extra genetic material affects the cognition and development of the child, but is not a blueprint that determines his or her potential, success or inability to lead a fulfilling, 

meaningful life.

One in every 691 babies in the United States is born with Down syndrome, making Down syndrome the most common genetic condition. Approximately 400,000 Americans have Down syndrome and about 6,000 babies with Down syndrome are born in the United States each year.

Down syndrome occurs in people of all races and economic levels, though older women have an increased chance of having a child with Down syndrome. A 35 year old woman has about a one in 350 chance of conceiving a child with Down syndrome, and this chance increases gradually to 1 in 100 by age 40. At age 45 the incidence becomes approximately 1 in 30. The age of the mother does not seem to be linked to the risk of translocation.

Although it is well established that the incidence of Down syndrome increases with the age of the mother, 80 percent of babies with Down syndrome are born to mothers under the age of 35. This is due to the higher fertility rates of women in this age group. The cause of the extra chromosome that leads to Down syndrome is still unknown and there is no known connection between parents’ activities before or during pregnancy and the occurrence of the Down syndrome.

Down syndrome is usually identified at birth by the presence of certain physical traits: low muscle tone, a single deep crease across the palm of the hand, a slightly flattened facial profile and an upward slant to the eyes. Because these features may be present in babies without Down syndrome, a chromosomal analysis, called karyotype, must be done to confirm the diagnosis.

Congenital heart defects, increased susceptibility to infection, respiratory problems and obstructed digestive systems occur more often in people with Down syndrome. Fortunately, advances in medicine have made most of these health problems treatable, and today, people with Down syndrome have an average life expectancy of 55 years, with many living in to their sixties, seventies and beyond.

All people with Down syndrome experience cognitive delays, but the effect is usually mild to moderate and is not indicative of the many strengths and talents that each individual possesses.

People with Down syndrome who receive appropriate medical care and are included in community life are expected to adapt successfully. Just like their peers, they attend school, develop friendships, maintain jobs, participate in important personal decisions and make positive contributions to the community. People with Down syndrome are more like their non-disabled peers than they are different, and they deserve the same opportunities.