What is Down Syndrome?
Down syndrome is a genetic disease in which there are 47 chromose instead of the normal amount which is 46. Down Syndrome is a disorder caused by an extra copy of chromosome 21.This disorder is also called trisonomy 21.Down Syndrome is caused by nondisjuction which means that a pair of chromosome did not separate during the formation of the egg or sperm.

How can you detect if your child has Down Syndrome?
During your pregnancy you can get screenings and also diagnostic test. Doctors will also check during your ultrasounds.Once your child is born if they have down syndrome they will have very distinct faces. Some common physical signs due to down syndrome are a flattenened nose, small ears and mouth, and upward slanting eyes Someone with Down Syndrome will live tell there about 50 years old.1 in 740 babies will be born with it.

Is there any effects on their development?
Children with down syndrome their physical development will be slower. Most don't get to average adult height. They also may have promplems with mental and social development. Some common promplem with them would be slow learning,impulsive behavior, poor judgement, and a short attention span.
Treatments
Someone with down syndrome can get physical and speech therapy. Sadly there is no cure yet.

Bibiography
http://lear.genetics.utah.edu/.