Ariana and Jongin
Kinefelter Syndrome

Nature of the Genetic Difficulty

  • Klinefelter syndrome occurs when men have an extra X chromosome. Instead of having a normal XY pattern, males who have this disease have XXY pattern.Nondisjuncton.gif
  • Klinefelter is the most common sex chromosome disease. 1 out of every 500 males have an extra X chromosome, but many don't have any symptoms.
  • It is not a life-threatening disease. With regular checkups and cautions, most men with Klinefelter syndrome live an active and fulfilling life.
  • Klinefelter syndrome is not inherited; it usually occurs as a random event during the formation of reproductive cells, it is called nondisjunction, and it results in a reproductive cell with an abnormal number of chromosomes. In this case containing an extra X chromosome.

Basis Facts of Disease

  • Klinefelter syndrome, also known as the XXY condition, is a syndrome in which males have an extra X chromosome. Instead of having the usual XY chromosome pattern, these men have an XXY pattern.
  • Klinefelter syndrome is named after Dr. Henry Klinefelter, who first described a group of symptoms found in some men with the extra X chromosome.
  • About one of every 500 males has an extra X chromosome, but many don't have any symptoms.Even though all men with Klinefelter syndrome have the extra X chromosome, not every XXY male has all of those symptoms.
  • Not all males with the condition have the same symptoms or to the same degree. Symptoms depend on how many XXY cells a man has, how much testosterone is in his body, and his age when the condition is diagnosed. The XXY condition can affect two main areas of development.
1) Physical 2) Social 3) Language
Physical Development
  • As babies males have weak muscles and reduced strength. They may sit up, crawl, and walk later than other infants. After around age four males tend to be taller and may have less muscle control and coordination than other boys their age.
  • During teenage years they often don't make as much testosterone as other boys. This can lead to a taller, less muscular body, less facial and body hair, and broader hips than other boys. As teens they may have larger breasts, weaker bones, and a lower energy level than other boys.
  • By adulthood males look similar to males without the condition, although they are often taller. They are more likely to have problems, such as autoimmune disorders, breast cancer, vein diseases, osteoporosis, and tooth decay.
  • Males can have normal sex lives, but they usually make little or no sperm. Between 95 percent and 99 percent of XXY males are infertile because their bodies don't make a lot of sperm.
  • Typically those with Klinefelter syndrome have abnormal body proportions, are unusually tall, have only a small amount of body hair, enlarged breasts, and sexual difficulties.
Social Development
  • As babies, XXY males tend to be quiet and undemanding. As they get older, they are usually quieter, less self-confident, less active, and more helpful and obedient than others.
  • As teens, males with Klinefelter syndrome tend to be quiet and shy. They may struggle in school and sports, because they have more trouble "fitting in".
  • However, as adults, XXY males live lives similar to men without the condition; they have friends, families, and normal social relationships.
Language Development
  • Those with Klinefelter's also have learning disabilities, difficulty with speech, and language development.
  • They tend to be quiet, sensitive, and unassertive, but as with all individuals the range varies.


Men with Klinefelter syndrom are at risk for following medical problems:
  • Autoimmune diseases, including type 1 diabetes, lupus, and hypothyrodism
  • Male breast cancer
  • Non-Hodgkin's lymphoma
  • Obesity
  • Osteoporosis
Since men with Klinefelter syndrom suffer from complications such as heart disease, they are at risk of premature death. Regular checkups and screening tests are helpful.
There is no cure yet, but there are many ways to treat the symptoms of the XXY condition.
Educational treatments – As children, many XXY males qualify for special services to help them in school. Teachers can also help by using certain methods in the classroom, such as breaking bigger tasks into small steps.
Therapeutic options – A variety of therapists, such as physical, speech, occupational, behavioral, mental health, and family therapists, can often help reduce or eliminate some of the symptoms of the XXY condition, such as poor muscle tone, speech or language problems, or low self-confidence.
Medical treatments – Testosterone replacement therapy (TRT) can greatly help XXY males get their testosterone levels into normal range. Having a more normal testosterone level can help develop bigger muscles, deepen the voice, and grow facial and body hair. TRT often starts when a boy reaches puberty. Some XXY males can also benefit from fertility treatment to help them father children.
One of the most important factors for all types of treatment is starting it as early in life as possible.

Sources Cited

"Klinefelter Syndrome." National Institutes of Health. N.p., 24 May 2007. Web. 18 Mar 2011.
"Question and Answers." NIH Office of Rare Diseases Research (ORDR). Web. 20 Mar. 2011.
Retrieved from ""