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Klinefelter's Syndrome

Symptoms and Causes
Possible Tests and Treatments
Inheritance? Under-Diagnosis?
Living life with Klinefelter's Syndrome
The History of Klinefelter's
Interesting and Important Facts

What is Klinefelter's Syndrome?
Klinefelter syndrome is a trismoic disorder that occurs in males who have three or more sex chromosomes. At least two of the chromosomes must be X chromosomes. The condition causes males to have some female-like physical features.

What is going on in the body?
Klinefelter syndrome affects only males. The presence of the Y chromosome assures that male sexual features will be present.
Because males with Klinefelter syndrome don't have the normal number of chromosomes, the body's natural balance is off which leads to:
  • underdevelopment of the testicles, a condition called hypogonadism, which usually leads to infertility
  • a taller-than-average height and a feminine body build


    What are the causes and risks of the condition?

    Klinefelter syndrome is caused when a fertilized egg has an extra sex chromosome. Most people have 46 chromosomes consisting of 23 pairs. One of these pairs will determine the sex of the embryo. The letter X designates the chromosome associated with being female. The letter Y designates the chromosome associated with being male. Females have two X chromosomes, and males have an X chromosome and a Y chromosome. If two X chromosomes are present, and there is also a Y chromosome, the person will be a male with the Klinefelter syndrome. This condition is also called 47,XXY. Some people with Klinefelter syndrome have more two X chromosomes and more than one Y chromosome. The physical features of Klinefelter syndrome are caused by abnormally low production of the male sex hormones.