Down syndrome is a disorder that includes a combination of birth defects; among children, some degree of mental retardation, characteristic facial features and, often, heart defects, increased infections, problems with vision and hearing, and other health problems. The severity of all of these problems varies greatly among affected individuals. Down syndrome is one of the most common genetic birth defects, affecting approximately one in 800 to 1,000 babies. It generally is caused by an extra chromosome, the structures in cells that contain the genetic information (genes). …
