- Down syndrome occurs when an individual has three, rather than two, copies
of the 21st chromosome. This additional genetic material alters the course
of development and causes the characteristics associated with Down syndrome.
- Down syndrome is the most commonly occurring chromosomal abnormality. One
in every 800 to 1,000 babies is born with Down syndrome.
- There are more than 350,000 people living with Down syndrome in the United States.
- Down syndrome affects people of all ages, races and economic levels.
- The incidence of births of children with Down syndrome increases with the
age of the mother. But due to higher fertility rates in younger women, 80
percent of children with Down syndrome are born to women under 35 years of
- People with Down syndrome have an increased risk for certain medical
conditions such as congenital heart defects, respiratory and hearing
problems, Alzheimer’s disease, childhood leukemia, and thyroid conditions.
Many of these conditions are now treatable, so most people with Down
syndrome lead healthy lives.
- Life expectancy for people with Down syndrome has increased dramatically
in recent decades – from 25 in 1983 to 56 today.
- 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.
- Quality educational programs, a stimulating home environment, good health
care, and positive support from family, friends and the community enable
people with Down syndrome to develop their full potential and lead
- People with Down syndrome attend school, find work, participate in
decisions that affect them, and contribute to society.
- Researchers are making great strides in identifying the genes on
Chromosome 21 that cause the characteristics of Down syndrome. Many feel
strongly that it will be possible to improve, correct or prevent many of the
problems associated with Down syndrome in the future.