Down Syndrome By Edward Pankowski And Jackson Schreyer
Down Syndrome: What is it? • Down Syndrome is a genetic disorder that results in lifelong mental retardation, developmental delays and other problems. Down Syndrome varies in severity, so developmental problems range from moderate to serious.
How often does it occur? • Down Syndrome is the most common genetic cause of severe learning disabilities in children. It occurs in roughly one in every 700 to 800 babies
Symptoms • Children with Down Syndrome have a distinct facial appearance, including: • Flattened facial features • Protruding tongues • Small head • Upward Slanting eyes • Unusually shaped ears • Infants with Down Syndrome may be born normal sized, but typically grow slowly and remain shorter than children of similar age. Children with Down Syndrome also have some degree of mental retardation but is more often moderate rather than severe.
Causes: Trisomy 21 • A child with Trisomy 21 has 3 copies of chromosome 21 as opposed to the normal 2 copies in all of his or her sperm cells. This form of Down Syndrome is caused by abnormal cell division during the development of the sperm cell or the egg cell. 90 percent of children with Down Syndrome are a result of Trisomy 21.
Causes: Mosaic Down Syndrome • This is a rare form of Down Syndrome, children with Mosaic Down Syndrome have some cells with abnormal cell division after fertilization.
Causes: Translocation Down Syndrome • Down Syndrome can occur when part of chromosome 21 becomes attached to another chromosome before or during conception. Children with Translocation Down Syndrome have two copies of chromosome 21 but have additional material from chromosome 21 stuck to the chromosome attached to the original strand of chromosome 21.
Other Causes • There are no known behavioral or evironmental factors that cause Down Syndrome and most cases aren’t inherited, but are caused by a mistake in cell division during the development of the egg, sperm, or embryo. • Translocation Down Syndrome is the only type that can be passed from mother/ father to child. If the father is a carrier for Down Syndrome, there is a 3% chance of the child having Down Syndrome. If the mother is a carrier for Down Syndrome, the risk increases to 12%.
Other Risks • A woman’s chances of having a child with Down Syndrome increase as she gets older because older eggs have a greater risk of improper chromosome division. At age 25 the odds of having a baby with Down Syndrome are between 1 in 700 and 1 in 800. At age 35, the risk increases to 1 in 400. At age 45, the risk goes up to 1 in 35. However, most children with Down Syndrome are born to young mothers because, statistically, young women have more babies. • Both men and women can pass the genetic translocation for down syndrome onto their children.
How is it diagnosed? • The diagnosis of Down Syndrome is carried out during pregnancy or shortly after birth. If a doctor suspects a baby has Down Syndrome, he can perform a karyotype, or an examination of the babies’ chromosomes to determine if they have any of the causes of down syndrome, such as trisomy 21.
FIN. • Now that you have learned more about Down Syndrome and the suffering millions of people go through, you can better understand Down Syndrome. Thanks for watching.
Works Consulted • Works Cited • "BBC - Health: Down's Syndrome." BBC - Homepage. Web. 06 Feb. 2011. <http://www.bbc.co.uk/health/physical_health/conditions/downssyndrome1.shtml>. • "Down Syndrome." Massachusetts General Hospital Home Page - Massachusetts General Hospital, Boston, MA. Web. 06 Feb. 2011. <http://www.mgh.harvard.edu/children/adolescenthealth/articles/aa_down_syndrome.aspx>. • "Down Syndrome." National Association for Down Syndrome. Web. 06 Feb. 2011. <http://www.nads.org/>. • Staff, Mayo Clinic. "Down Syndrome - MayoClinic.com." Mayo Clinic. Web. 06 Feb. 2011. <http://www.mayoclinic.com/health/down-syndrome/DS00182>.