Definition:
Down syndrome (DS) is a developmental disability caused by an extra chromosome. This abnormality impairs physical and neurological development, resulting in mental retardation and such physical characteristics as poor muscle tone, short neck, broad hands and feet, and slanting eyes. Children with DS may also have respiratory problems, gastrointestinal problems, spinal problems, heart problems, and problems with hearing and language.
Also Known As: Trisomy 21
