Down syndrome is set of mental and physical symptoms that result from having an extra copy of chromosome 21. Even though people with Down syndrome may have some physical and mental features in common, symptoms of Down syndrome can range from mild to severe. Usually, mental development and physical development are slower in people with Down syndrome than in those without it.

People with the syndrome may also have other health problems. They may be born with heart disease. They may have dementia. They may have hearing problems and problems with the intestines, eyes, thyroid and skeleton.

The chance of having a baby with Down syndrome increases as a woman gets older. Down syndrome cannot be cured. However, many people with Down syndrome live productive lives well into adulthood.