XXY, 47

Klinefelters Syndrome


Klinefelters syndrome is caused by nondisjunction. This happens when something fails during meiosis. In this particular disorder, an egg or sperm with an extra X joins with an normal egg or sperm, leading to an embryo with three sex chromosomes. It mainly affects the X chromosome.
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Can it be detected during gestation?

The only way to be diagnosed with Kilnefelters is by a karyotype test. Many times there are no prenatal test done, as it carries a small risk of miscarriage, unless there is a family history of chromosomal disorders or other medical issues. In order for the karyotype to be created the pregnant woman must go through a small procedure known as amniocentesis in order to collect a tissue or liquid sample for the test.

How do you know?

As mentioned before, the only way to accurately diagnose this disease is through a karyotype. Some symptoms may show, but they occur in many different varieties across the board. Many men only discover they have this syndrome after visiting fertility clinics. The disorder mainly affects sexual development.

Common Symptoms:

  • Taller than normal with in-proportionate limbs.
  • Underdeveloped testes
  • Low hormone levels
  • Minimal body hair growth
  • Development of breast tissue


Minimal studies have been conducted to show what parts of the world have the most people with Klinefelters disease. In the United States, 1 in 500 to 1000 males are born with this syndrome. Only males can have this disorder and it is not inherited in any way. This disorder occurs when a random change occurs during the creation of reproductive cells.


Many people who have this disorder may not even know and can live a full life whether they know or not. The majority of men diagnosed with this disease find out after visiting a fertility clinic. Once diagnosed, they will find out that they are unable to produce sperm that can lead to an embryo being developed; they are infertile. Some treatment options for this disorder may include hormone treatments. A person with this disorder may take testosterone to develop more male like characteristics or estrogen to develop female like characteristics. Overall, a person with this condition should have the ability to live a full life so long as they have the right tools.


The National Human Genome Research Institute is currently not conducting any clinical trials regarding Klinefelters Syndrome. Any new treatments or cures are not expected to be coming out soon, as far as the general public knows.

Additional Facts

  • Klinefelters Syndrome is one of the most common genetic disorders with 1 - 500 to 1000 males being born with this disorder.
  • The disorder was named after Dr. Harry Klinefelter when he first reported symptoms in 1942.