Our bodies are made up of millions of cells. In each cell there are 46 chromosomes. The DNA in our chromosomes determines how we develop. Down syndrome is caused when there is an extra chromosome. People with Down syndrome have 47 chromosomes in their cells instead of 46. They have an extra chromosome 21, which is why Down syndrome is also sometimes known as trisomy 21.

Translocation DS Karyotype 1

Although we know how Down syndrome occurs, we do not yet know why it happens. Down syndrome occurs at conception, across all ethnic and social groups and to parents of all ages. It is nobody's fault. There is no cure and it does not go away. It is the most common chromosome disorder that we know of. One of every 700-900 babies born worldwide will have Down syndrome, although this number is lower in Australia. Down syndrome is not a new condition. People with Down syndrome have been recorded throughout history.

Most of the young people growing up with Down syndrome today will lead quite ordinary lives in the community. They are unique, with their own thoughts, interests, talents and abilities.  They grow up, go to school, get a job - just like everyone else.  People with Down syndrome are capable of living full and inspired lives as a valued member of their family and community.

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About Down syndrome_Factsheet