Breanna's+Mutation+Project

toc  = Down Syndrome =

__ Introduction- __
There are many different types of chromosomal mutations, such as Down Syndrome. According to the Prentice Hall Biology Book, a chromosomal mutation is "changes within the number or structure of chromosomes". There are four different types of chromosomal mutations. These mutations include deletion, duplication, inversion, and translocation. Down Syndrome is a duplication chromosomal mutation. This mutations occurs when an extra copy of chromosome 21 is produced. This mutation was named after the British doctor, John Langdon Down, who described it in 1866. Down Syndrome was identified to be a 21 [|trisomy] by Jerome Lejeune in 1959. This mutation occurs about once per every 800 to 1,000 births in the world.

__ Genetics- __
Down Syndrome is 21st trisomy. A 2st1 trisomy is when there are more then two copies of the 21st chromosome. Instead of having on 21st chromosome from each parent there is an extra copy of the 21st trisomy. This process occurs from [|meiotic] [|nondisjunction.] When the gamate is produced with an extra 21st chromosome. Therefore when the embryo is formed it has 47 chromosomes, because there is three copies of the 21st chromosome instead of two. 88% of the time when Down Syndrome occurs it is produced from the maternal gamate.



__ Characteristics of Down Syndrome- __
People with down syndrome usually have distinct features. Some features can be found within the face of the person. For example a person with Down Syndrome may have more of a flattened nose compared to a person with out Down Syndrome. A person may also have a small ears or a small mouth with a large tongue, compared to a normal person. A difference can also be seen in hands and feet in people with Down Syndrome. People with this mutation usually have a single crease in the palms of their hands, instead of a double crease. There is also a larger space between the big toe and second toe in people with Down Syndrome.



__ Medical Problems & Treatments- __
Down Syndrome is not a curable mutation, but there are many treatments. People with this mutation usually have more medical problems then normal people. Some of these medical problems include muscle, joints, and hearing problems. Some people even have seizures and leukemia. Some of the treatments available for people with Down Syndrome include physical therapies, surgical treatments, and speech therapies. Physical therapy usually involves motor skills and the development of the muscles. Speech therapy is usually given to children with Down Syndrome. Since people with Down Syndrome usually have larger tongues, they are given speech.

__ Resources: __
http://en.wikipedia.org/wiki/Down_syndrome http://downsyndrome.about.com/od/featuresofdownsyndrome/a/featuresess_ro.htm http://downsyndrome.about.com/od/downsyndrometreatments/a/Treatmentess_ro.htm http://www.youtube.com/watch?v=ycrPCTP2mFE&feature=related