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Klinefelter Syndrome Key Vocabulary Nondisjunction - "the failure of chromosomes to separate and segregate into daughter cells at division." Aneuploidy - "the condition of having an abnormal number of chromosomes" Trisomy - "the presence of three copies of a particular chromosome in cells that normally have two copies of each chromosome." What is Klinefelter Syndrome? Klinefelter syndrome is a genetic disorder that affects the bodily development of the infected, male individual. Causes
 * Klinefelter's syndrome is the result of nondisjunction, when the "x" chromosomes fail to separate during the formation of a sperm or egg. In other words, a single sperm, which can only carry a "y" chromosome, is carrying an "xy" chromosome, or a single egg, which normally carries a single "x" chromosome, is carrying an "xx" chromosome. (Fig. 1)
 * During fertilization, the extra "x"chromosome is still present, and joins the normal "xy" chromosomal pair, forming an "xxy" chromosome (Fig. 2).
 * More serious variants of Klinefelter's syndrome are caused when both the egg AND the sperm undergo nondisjunction, forming "xxxy," or "xxxxy." These variants cause much more defined, serious symptoms, such as impaired mental health/ capacity, etc.
 * [[image:glemaklinefelter/1277536908.jpg width="408" height="348" align="left" caption="Figure 1"]] ||
 * Figure 1. ||
 * [[image:depositphotos_13500067-Klinefelter-syndrome-eps8.jpg width="286" height="315"]] ||
 * Figure 2. ||

Symptoms *Symptoms are not usually visible until puberty, because many of the clear symptoms are the result of a lack of testosterone, a hormone that is produced during puberty.* Symptoms (during and after puberty) include: Childhood symptoms include: Treatments
 * Low testosterone production.
 * Low sperm count/ infertility
 * Abnormally long limbs, fingers, toes, feet, hands,
 * Abnormally tall body structure.
 * Reduced muscle mass
 * Reduced body/ facial hair
 * Learning disabilities
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">Impaired speech/ language development.
 * [[image:glemaklinefelter/nondisjunction.jpg caption="nondisjunction.jpg"]] ||
 * Figure 3. Note the difference between "xxy" and "xxxy." ||
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">A Chromosome Analysis (Karyotype) can be used to detect Klinefelter's syndrome with a sample of blood or tissue.
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">Testosterone treatments/ injections can be given to the carrier of Klinefelter's syndrome. If a testosterone treatment is started early in puberty, the child may develop more normally than they would without it.
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">Infertility is a permanent symptom for a majority of victims. For some, however, there is still a small amount of sperm production. For these few victims, doctors can perform an "intracytoplasmic sperm injection (ICSI), where doctors can "transport" the few active sperm from the male to a female using a biopsy needle.
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">Speech therapy/ extra educational support is not out of the question for the victims.

Other Information
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">Klinefelter's syndrome was discovered by Dr. Harry Klinefelter at the Massachusetts General Hospital in Boston in 1942.
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">Because Klinefelter's syndrome is the result of a random genetic change, it can not be inherited, should the victim be able to have children after the treatments.
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">Many men, who have mild ("xxy") Klinefelter's syndrome, can live full lives without being diagnosed.
 * <span style="color: #000080; font-family: Georgia,serif; font-size: 20.8px;">1 in 500 babies are born with Klinefelter's Syndrome

References <span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;">--United States. U.S. National Library of Medicine.Klinefelter syndrome. 2013. Web. <[]>.

<span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;">--Mayo Clinic Staff,. "Klinefelter Syndrome." Mayo Clinic(2010): n.pag. Mayo Clinic. Web. 10 Feb 2013. <[]>.

<span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;">--Mayo Clinic Staff,. "Klinefelter Syndrome Treatments and drugs." Mayo Clinic (2012): n.pag. Mayo Clinic. Web. 10 Feb 2013. <span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;"><[]>. <span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;">unidentified, author. "Klinefelter Syndrome - Topic Overview." WebMD (2011): n.pag. WedMD. Web. 10 Feb 2013. <[]>.

<span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;">--Schoenstadt, MD, Arthur. "History of Klinefelter Syndrome." eMEDTV (2006): n.pag. eMEDTV. Web. 10 Feb 2013. <[]>.

<span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;">--Matthews, Anne L. "Klinefelter syndrome." World Book Student. World Book, 2013. Web. 11 Feb. 2013. <span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;">--Matthews, Anne L. "Trisomy." World Book Student. World Book, 2013. Web. 11 Feb. 2013. <span style="color: #4802a7; font-family: Georgia,serif; font-size: 20.8px;">--Sullivan, Beth A. "Aneuploidy." World Book Student. World Book, 2013. Web. 11 Feb. 2013.