Down's syndromeOverview

Down's syndrome, also known as Down syndrome or trisomy 21, is a condition you're born with. Most people who have Down's syndrome lead healthy and fulfilled lives.

Down's syndrome, also known as Down syndrome or trisomy 21, is a condition you're born with. Most people who have Down's syndrome lead healthy and fulfilled lives.

Characteristics of Down's syndrome

Everyone born with Down's syndrome will have some level of learning disability, but this will be different for each person.

Find out more about the characteristics of Down's syndrome

Causes of Down's syndrome

Down's syndrome is caused by an extra chromosome in a baby's cells.

In most cases, this is not inherited – it's simply the result of a one-off genetic change in the sperm or egg.

There's a small chance of having a child with Down's syndrome with any pregnancy, but the likelihood increases with the age of the mother.

For example, a woman who's 20 has about a 1 in 1,500 chance of having a baby with Down's, while a woman who's 40 has a 1 in 100 chance.

There's no evidence that anything done before or during pregnancy increases or decreases the chance of having a child with Down's syndrome.

Find out more about the causes of Down's syndrome

Living with Down's syndrome

There's support available to help children and adults with Down's syndrome lead healthy, fulfilling lives.

This includes:

  • access to good healthcare – including a range of different specialists
  • support for your child's development – this may include speech and language therapy and physiotherapy 
  • organisations like the Down's Syndrome Association, who provide information and support, and can also put you in touch with other families who have a child with Down's syndrome

Lots of people with Down's syndrome are able to go to mainstream schools, leave home, have relationships, work and lead largely independent lives.

Find out more about living with Down's syndrome

Social care and support guide

If you:

  • need help with day-to-day living because of illness or disability
  • care for someone regularly because they're ill, elderly or disabled, including family members

Our guide to care and support explains your options and where you can get support.

Health conditions associated with Down's syndrome

Some health conditions are more common in people with Down's syndrome, including:

  • heart conditions
  • hearing and vision problems
  • thyroid conditions
  • infections, such as pneumonia

Your child may be checked by a paediatrician more often to help them stay in good health.  

If you have any concerns about your child's health, talk to your GP, health visitor or paediatrician.

Find out more about the health conditions asscociated with Down's syndrome

Screening for Down's syndrome

Sometimes parents find out their baby has Down's syndrome during pregnancy because of screening tests.

All pregnant women are offered screening tests for Down's syndrome.

Screening tests cannot tell you for certain if your baby has Down's syndrome, but they can tell you how likely it is.

If screening tests show there's a chance your baby has Down's syndrome, you can, if you wish, have further tests to find out for certain if your baby has the condition.

These include:

  • chorionic villus sampling (CVS) – a small sample of the placenta is tested, usually during weeks 11 to 14 of pregnancy
  • amniocentesis – a sample of amniotic fluid is tested, usually during weeks 15 to 20 of pregnancy

If these tests show that your baby has Down's syndrome, you and your baby's other parent will be offered counselling so you can talk about what this means.

You may also be offered an appointment to meet a doctor or other health professional who works with children with Down's syndrome.

They can tell you more about the condition and answer any questions you have.

Find out more about screening for Down's syndrome

More help and support

If you'd like more information about Down's syndrome, you can visit the Down's Syndrome Association or call their helpline on 0333 121 2300.

Information about your child

If your child has Down's syndrome, your clinical team will pass information about him or her on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

This service supports research to help clinicians and people with Down's syndrome. You can opt out of the register at any time.

Find out more about the register

Page last reviewed: 30/04/2017
Next review due: 30/04/2020