My brother has Down Syndrome and we were told it isn't hereditary.
Hi!
Down Syndrome is a genetic disorder, but it is not a hereditary disorder. Hence, it does not run in families. It happens due to genetic changes during formation of a baby. However, people carrying balanced translocation between chromomsome 21 and other chromosomes are more likely to give birth to a child with Down Syndrome. Hence, if you have a family member with Down Syndrome, genetic counseling is given to find out this possibility. Hope this helps. Take care!