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About Down Syndrome

What Is Down syndrome?

Down syndrome, or Trisomy 21, as it is called within the medical community, is caused by an extra copy of the 21 st chromosome. An error in cell division, called non-disjunction, happens at the moment of conception for reasons we still do not understand. The extra chromosome causes varying degrees of mental retardation and physical abnormalities. Most people with Down syndrome have mental retardation falling in the mild to moderate range, and they have speech and language difficulties. Persons with Down syndrome can also have a wide range of health problems, including congenital heart defects, obstructed digestive systems, thyroid conditions, hearing problems, leukemia, increased susceptibility to infection, sleep apnea, and respiratory problems. Individuals with Down syndrome also are at a higher risk of developing Alzheimer's disease, autism, and many neurological and psychiatric disorders, including obsessive-compulsive disorder and depression.

How many people in the United States have Down syndrome?

About one in every 800 American babies is born with Down syndrome, and it is estimated that about 350,000 people in the United States live with this condition today. There is a false impression that pregnancy screening has eliminated or substantially reduced the incidence of Down syndrome in the population. Despite years of screening, the Down syndrome population in the country has remained stable.

Isn't Down syndrome too complex to treat and once someone is born with it, isn’t it too late?

For many years, scientists believed that Down syndrome was too complex to understand, and they believed that there was no way to reverse or reduce the severity of cognitive impairment. However, scientific advances have made it possible to understand how specific genes are linked to specific abnormalities in the structure and function of the brain. Although the 21st chromosome has hundreds of genes, researchers believe that there may be only a handful that significantly impact cognition. Using advanced techniques and methods, researchers believe they will be able to isolate the effects of these specific genes and determine how their expression in the brain can cause problems with cognition. Once researchers define the mechanisms responsible for cognitive dysfunction, they can begin the process of discovering treatments that enhance brain function, including cognition. Specifically, researchers believe that if they can find a drug that can "turn down" the over-expression of certain genes in the brain, they will be able to restore or significantly improve cognitive functioning in persons with Down syndrome. Today we can boldly predict that Down syndrome is not too complex to understand and it is not too difficult or too late to treat.

Is a treatment a cure?

No. Once a baby is born with Down syndrome, he or she will always have an extra chromosome. However, research may be able to reverse or ameliorate the affects of the extra chromosome, particularly with regard to the degree of cognitive impairment. No one can say for sure how much cognition could be improved. However, even a modest improvement of 10 IQ points could have enormous impact on the life of a person with Down syndrome. Because the majority of individuals with Down syndrome fall into the mild to moderate range of cognitive impairment, an extra 10 IQ points would enable most persons with Down syndrome to function much more independently in school and the workplace.