A genetic condition that usually causes some level of learning disability and characteristic physical features.
Each person with Down's syndrome is affected differently, but most share a number of physical characteristics and developmental problems.
Read more about Down's syndrome (NHS Choices).
Worried about Down's syndrome?
You're usually screened when you're pregnant to see if your baby might have Down's syndrome, but in many cases it can only be diagnosed after birth.
If you're worried about your child, speak to a health professional. There are many professionals experienced in caring for children with Down's syndrome: