Down’s syndrome


Each person with Down’s syndrome is affected differently, but most share certain physical characteristics and development problems. 

Physical characteristics

People with Down’s syndrome often have certain physical characteristics. Not everyone will have all of them, but they may include:

  • floppiness (hypotonia)
  • small nose and flat nasal bridge
  • small mouth with a tongue that may stick out
  • eyes that slant upwards and outwards
  • a flat back of the head
  • broad hands with short fingers
  • their palm may have only one crease across it
  • below-average weight and length at birth

But people with Down’s syndrome don’t all look the same – they also look like their parents and family.



Delayed development

All children with Down’s syndrome have some degree of learning disability and delayed development, but this varies widely between individual children.

Children with Down’s may be slower to learn skills like sitting, standing, walking, and talking. They will develop these skills eventually, it just takes more time.

Around 1 in every 10 children with Down’s also have other conditions, such as autism spectrum disorder (ASD) or attention deficit hyperactivity disorder (ADHD).

Children with Down’s syndrome often need more support as they grow up, including extra help at school.

Read more about living with Down’s syndrome.

Health problems

There are some conditions more common in people with Down’s syndrome.

These include:

  • problems with the heart and bowel
  • difficulties with hearing and vision
  • a higher risk of infections


Down’s syndrome is a genetic condition that happens as a result of an extra chromosome (chromosome 21).

Chromosomes explained

Our bodies are made up of cells that contain genes. Genes are grouped in thread-like structures called chromosomes.

These contain detailed genetic instructions for lots of different things, including:

  • how a baby’s cells develop
  • their gender
  • their eye colour

Usually, cells contain 46 chromosomes – 23 from the mother and 23 from the father.

In people with Down’s syndrome, all or some of the cells in their bodies contain 47 chromosomes instead, as there’s an extra copy of chromosome 21. This extra gene causes the characteristics of Down’s syndrome.

In most cases, Down’s syndrome isn’t inherited, it’s just the result of a one-off genetic change in the sperm or egg.

What are the chances of having a baby with Down’s syndrome?

With every pregnancy, there’s a small chance of having a baby who has Down’s syndrome.

Some people are more likely to have a child with Down’s than others.

The main thing that increases the chance of having a baby with Down’s syndrome is the mother’s age.

For example, a woman who is:

  • 20 years of age has a 1 in 1,500 chance
  • 30 years of age has a 1 in 800 chance
  • 35 years of age has 1 in 270 chance
  • 40 years of age has a 1 in 100 chance
  • 45 years of age has a 1 in 50 or greater chance

However, babies with Down’s syndrome are born to women of all ages.

Your chance of having a child with Down’s syndrome is also increased if you previously had a child with Down’s. For most people, this chance is still small (around 1 in 100).

There’s around a 1 in 2 chance of a child having Down’s syndrome if one of his or her parents has the condition.