Down syndrome is a disorder that is caused by an extra number 21 chromosome. This affects one in every 800 births worldwide, and causes birth defects. Also, there is no cure for Down syndrome. Most research says that there have always been people suffering from Down syndrome. Dr Jon Langdon Down was the first person to recognize this. Down syndrome was also known as "mongolism" because the people who had it seemed to resemble Mongolian Asians. This term is no longer used because it is inappropriate and offensive to others. There are approximately 350,000 people suffering from Down syndrome in the United States. Some physical features of Down syndrome would be a small mouth and nose, short fingers, and short necks.
When a child is born with Down syndrome it is because there is an extra copy of chromosome 21. This can occur in many ways but it is still unknown.
Trisomy 21 is the most common chromosomal irregularity that causes Down syndrome. This is a defect where a third copy of chromosome 21 is in every cell in the body of the person. The age of the mother is one of the reasons for Trisomy 21. There are other chromosomal irregularities that cause Down syndrome. The first one is call translocation which is when a piece of the 21st chromosome attaches itself to another chromosome. Also if there are two 21st chromosomes the child will have features of the disorder. If there is one of the 21st chromosome the person won't have Down syndrome features, but their children could. Another chromosomal irregularity is Mosaic Down syndrome. This is when only some cells in the body have the extra chromosome.
People who are born with Down syndrome suffer from many distinct physical features. These features include eyes that...