Overview. Klinefelter syndrome is
a genetic condition that results when a boy is born with an extra copy of the X chromosome
. Klinefelter syndrome is a genetic condition affecting males, and it often isn’t diagnosed until adulthood.
What is meant by Klinefelter syndrome?
Listen to pronunciation. (KLINE-fel-ter SIN-drome)
A genetic disorder in males caused by having one or more extra X chromosomes
. Males with this disorder may have larger than normal breasts, a lack of facial and body hair, a rounded body type, and small testicles.
What causes Klinefelter syndrome?
Klinefelter syndrome is caused by
an additional X chromosome
. This chromosome carries extra copies of genes, which interfere with the development of the testicles and mean they produce less testosterone (male sex hormone) than usual.
What happens if you have an XXY chromosome?
As XXY males
enter puberty
, 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, XXY males may have larger breasts, weaker bones, and a lower energy level than other boys.
What are two characteristics of Klinefelter syndrome?
Males who have Klinefelter syndrome may have the following symptoms:
small, firm testes, a small penis, sparse pubic, armpit and facial hair
, enlarged breasts (called gynecomastia), tall stature, and abnormal body proportions (long legs, short trunk).
Is Klinefelter syndrome a disability?
If you or your dependent(s) are diagnosed with Klinefelter Syndrome and experience any of these symptoms, you may be eligible for
disability
benefits from the U.S. Social Security Administration.
Who is most likely to get Klinefelter syndrome?
Klinefelter syndrome results when
a boy is born
with at least 1 extra X chromosome. This is written as XXY. Klinefelter syndrome occurs in about 1 out of 500 to 1,000 baby boys. Women who get pregnant after age 35 are slightly more likely to have a boy with this syndrome than younger women.
What is the life expectancy of a person with Klinefelter syndrome?
According to research, Klinefelter syndrome can
shorten your life expectancy up to two years
. However, you can still live a long, full life with this condition. The earlier you get treatment, the better your outlook will be.
What is the most common treatment for Klinefelter syndrome?
Treatment of Klinefelter Syndrome
One common treatment is
testosterone replacement therapy
. It can start at puberty and can spur typical body changes, such as facial hair and a deeper voice. It can also help with penis size and stronger muscles and bones, but it won’t affect testicle size or fertility.
What age is Klinefelter syndrome diagnosed?
Klinefelter syndrome usually is not diagnosed
until the time of puberty
. At this point, the boy’s testicles fail to grow, and you may start to notice other symptoms.
Can females have XXY syndrome?
Klinefelter syndrome affects males only;
females cannot have it
. Klinefelter syndrome results from a genetic abnormality in which males have an extra copy of the X chromosome.
Are XXY males infertile?
Between 95% and 99% of XXY men are infertile
because they do not produce enough sperm to fertilize an egg naturally. But, sperm are found in more than 50% of men with KS.
Can you be a girl with a XY chromosome?
The X and Y chromosomes are called “sex chromosomes” because they contribute to how a person’s sex develops. Most males have XY chromosomes and most women have XX chromosomes. But there are girls and women who have XY chromosomes. This can happen, for example, when a girl has androgen insensitivity syndrome.
How is Klinefelter’s diagnosed?
Blood or urine samples can reveal abnormal hormone levels
that are a sign of Klinefelter syndrome. Chromosome analysis. Also called karyotype analysis, this test is used to confirm a diagnosis of Klinefelter syndrome. A blood sample is sent to the lab to check the shape and number of chromosomes.
CAN XXY have babies?
It is possible that an XXY male could get a woman pregnant naturally
. Although sperm are found in more than 50% of men with KS
3
, low sperm production could make conception very difficult.
What is the risk for inheritance of Klinefelter syndrome?
Klinefelter syndrome is not inherited
; the addition of an extra X chromosome occurs during the formation of reproductive cells (eggs or sperm) in one of an affected person’s parents.
