About Down syndrome
Down syndrome occurs equally among children of all races and from all backgrounds.
Although people with Down syndrome share common genetic characteristics, each individual is still unique.
Down syndrome is a genetic condition
Most people with Down syndrome have an additional copy of chromosome 21 in every cell. This is present
from the point of conception and influences development before and after birth and throughout the rest
of life. There are around 500 genes on chromosome 21 and although great advances have been made we still
know little about their precise actions.
People with Down syndrome are also individuals
Although people with Down syndrome share common genetic characteristics, each individual is still unique.
There is wide variability in medical and developmental outcomes for people with Down syndrome for reasons
that are not yet understood.
Cause
We do not know precisely how or why some people are born with an additional chromosome. No environmental
or genetic factors leading to Down syndrome have been identified.
Common among all people in all places
We do know that Down syndrome occurs equally among children of all races and from all backgrounds. It
is the most common cause of learning disability with a known genetic origin.