An eight-year-old boy with Down syndrome

Down syndrome (or trisomy 21) is a genetic disorder. Most people with Down Syndrome have an extra copy of chromosome 21, or part of it.

Down syndrome causes a mental handicap. It may be mild or severe. The average IQ of a young adult with Down syndrome is 50, equivalent to the mental age of an 8- or 9-year-old child, but it truly depends on the person. This can vary widely, but most individuals need supervision if they are to live their lives in a satisfactory way. Children who have this condition take more time to learn new things.