Defining Down syndrome is not as simple as saying it is an autism spectrum disorder.
Many sufferers have normal brain development, but do not necessarily meet the diagnostic criteria.
It is not clear why this is the case.
Some have normal brains and some do not.
Some may be very intelligent but not necessarily social.
Others have normal social skills but are not particularly social.
Some suffer from ADHD and may have problems concentrating, but their brains are healthy and not damaged.
In the end, a person’s definition of Down syndrome varies from person to person.
Some people may have a mild or milder form of the condition.
Others may have normal cognitive abilities, but may also have other problems.
The definition varies depending on the symptoms of the disorder, as well as their age, gender and race.
Down syndrome can be a complex diagnosis with many complex factors.
If you are one of these people, the BBC is asking you to consider whether you qualify for help.
It also asks you to share your experience.
This article was produced by the BBC News website.