What is Down syndrome?

Down syndrome (or Trisomy 21) is a condition in which a person has an extra

Chromosomes are “packages” of genes in the body. They determine how a
baby’s body forms and functions as it grows.

Around 1 in every 800 babies will be born with Down syndrome.

Down syndrome occurs naturally – there is no known cause.

Down syndrome usually causes varying degrees of intellectual and physical
disability and associated medical issues.


“Chromosomes R Us” is a short film by actors with Down syndrome explaining how Trisomy 21 occurs. 

Made by Shabang Inclusive Learning in collaboration with Mediapreview, Huddersfield, UK, this film was made possible by generous funding by BBC Children in Need. 

Down syndrome answers

The best people to answer many questions about Down syndrome are people with Down syndrome.

The Canadian Down Syndrome Society found the most asked questions on Google and asked 10 Canadians with Down syndrome to give their answers. Check out the Down Syndrome Answers video project:


Just like you

People with Down syndrome have an inherent right to be accepted and included as valued and equal members of the community.

The video ‘Just Like You’ is an example of how this is happening. This video was jointly funded, produced and directed by two Kansas City, United States non-profit organisations.

Down syndrome explained

Down Syndrome International has produced a ‘Down syndrome explained’ pack which provides bitesize introductions to some of the key topics relevant to people with Down syndrome, including:

What is Down syndrome?
New parents
Advocacy and human rights
Inclusive participation

Complete the form to request a FREE digital copy of our ‘Down syndrome explained’ pack:


Sign up!

Sign up to hear from the World Down Syndrome Day team about how you can get involved.

You will also get access to our FREE WDSD resources including guides for advocacy, schools and organisations, posters, templates and lots more to help you to mark this important day.

Together we will create a single global voice advocating for the rights, inclusion and well being of people with Down syndrome.