| Every year, one child in every 800 to 1,000 births will | | | | the population of people with the disorder. |
| be born with a condition known as Down syndrome. | | | | Translocation occurs when part of chromosome 21 |
| Down syndrome is a disorder in which the child has | | | | breaks off and attaches to another chromosome, |
| extra genetic material. This extra genetic material | | | | changing the genetic makeup. In this form of Down |
| causes the baby to develop differently in the womb. | | | | syndrome, each cell has the normal 46 chromosomes, |
| This abnormal development occurs during the early | | | | but there is extra genetic material from the broken |
| stages of cell division, soon after conception.There is | | | | off chromosome.The third and final form is called |
| no known reason for Down syndrome or a cure for | | | | Mosaicism, and is the rarest form of Down |
| it.The disorder came by its name when an English | | | | syndrome, occurring in only 2% of all cases. |
| physician, John Langdon Down, published a description | | | | Mosaicism happens when some of the cells in the |
| of the characteristics of a person with the condition | | | | forming embryo have 46 chromosomes, and some |
| in 1886. Since Dr. Down was the first person to give | | | | have 47. Thus, the alternating pattern gives it the |
| the syndrome a name, the disorder is known as | | | | name Mosaicism.People with Mosaicism may not be as |
| Down syndrome.The Common Forms of | | | | affected with the physical and/or developmentally |
| DownsThere are three distinct forms of Down | | | | delayed characteristics of those born with the other |
| syndrome. The most common form is Trisomy 21. | | | | two forms of Down syndrome.Common Physical |
| This is when a child has an extra chromosome | | | | TraitsBabies with Down syndrome are usually |
| 21.Instead of having 46 chromosomes in each cell (23 | | | | diagnosed at birth or shortly thereafter. Because |
| from the father and 23 from the mother), he has 47. | | | | Down syndrome affects a child physically, there will |
| Ninety-five percent of children born with Down | | | | be certain features that an alert doctor or nurse will |
| syndrome have Trisomy 21.Translocation is another | | | | pick up on. Most children with the syndrome will have |
| form of Down syndrome and makes up 3 to 4% of | | | | some or all of these traits. |