In modern day society there are a plethora of illnesses and genetic defects that people are born with. Among them is a defect called Down syndrome. This syndrome is one that is quite widespread and occurs in 1 of 800 to 1,000 live births. Many, if not all of us have been in contact or at least knew of someone with Down syndrome. Even though you may have heard the term Down syndrome, what it is exactly is still a mystery. This paper will try to explain, among others, the types, causes, effects and characteristics of Down syndrome.
             John Langdon Down was an English physician in the 19th century. He is the one credited with classifying this genetic defect in his essay published in England in 1866. Down was the head of a children's asylum where he noted that some children have the same distorted features. Due to this distortion, he called them Mongoloids. It wasn't until 1960 that the name Mongoloid was replaced with Down's syndrome; in 1970 it was changed to Down syndrome, since he himself wasn't afflicted by this defect. The fact that it occurs due to chromosomal abnormalities was not documented until the 1930's.
             Down syndrome is the most common genetic birth defect that is associated with mental retardation. It is also the most identifiable. Down syndrome know no boundaries and is occurs equally in all races and levels of society. The cause of this defect is a chromosomal abnormality where due to some "accident" in cell development results in 47 chromosomes instead of that normal 46. Due to this extra chromosome the body and that brain undergo changes. Down syndrome is usually diagnosed in babies shortly after birth according to the results of a chromosome test.
             Up to this point in medical history 3 types of Down syndrome have been identified. The most common one is Trisomy 21 where there is extra material on the chromosome pair 21. This occurs in 95% of all cases of Down syndrome and is...