Down syndrome


What is Down syndrome?

Down syndrome is a set of physical and mental traits caused by a gene problem that happens before birth. Children who have Down syndrome tend to have certain features, such as a flat face and a short neck. They also have some degree of intellectual disability. This varies from person to person. But in most cases it is mild to moderate.

Down syndrome is a lifelong condition. But with care and support, children who have Down syndrome can grow up to have healthy, happy, productive lives.

What causes Down syndrome?

Down syndrome is caused by a problem with a baby’s chromosomes. Normally, a person has 46 chromosomes. But most people with Down syndrome have 47 chromosomes. In rare cases, other chromosome problems cause Down syndrome. Having extra or abnormal chromosomes changes the way the brain and body develop.

Experts don’t know the exact cause, but some things increase the chance that you’ll have a baby with Down syndrome. These things are called risk factors.


Your risk of having a baby with Down syndrome is higher if:

  • You are older when you get pregnant. Many doctors believe that the risk increases for women age 35 and older.
  • You have a brother or sister who has Down syndrome.
  • You had another baby with Down syndrome.