The effects of Klinefelter syndrome vary from person to person, and signs and symptoms of the syndrome can appear differently at different ages. If you suspect that you or your son may have Klinefelter syndrome, your doctor will examine your or your son's genital area and chest, as well as conduct tests to check reflexes and mental functioning.
Chromosomal analysis: Also called karyotype, this involves drawing a small sample of blood, which is sent to a lab to check the shape and number of chromosomes. Hormone testing: This can be done through blood or urine samples and can detect if abnormal sex hormone levels — a sign of Klinefelter syndrome — are present.
While there is no cure for sex chromosome changes caused by Klinefelter syndrome, treatments can help minimize effects, especially when they're started early. Treatment may include the following. Testosterone replacement therapy: Since males with Klinefelter syndrome don't produce enough testosterone , undergoing testosterone replacement therapy at the onset of puberty can allow a boy to undergo the body changes that normally occur at puberty, such as developing a deeper voice, growing facial and body hair, and increasing muscle mass and penis size.
Testosterone therapy can also improve bone density and reduce the risk of fractures, but it will not enlarge the testicles or help with infertility.
Fertility treatments: Intracytoplasmic sperm injection ICSI can help men with minimal sperm production by removing sperm from the testicle and injecting it directly into a woman's egg. The X chromosome is not a "female" chromosome and is present in everyone. The presence of a Y chromosome denotes male sex. Boys and men with Klinefelter syndrome are still genetically male, and often will not realise they have this extra chromosome, but occasionally it can cause problems that may require treatment.
Klinefelter syndrome does not usually cause any obvious symptoms early in childhood, and even the later symptoms may be difficult to spot. Most boys and men with Klinefelter syndrome will not be significantly affected and can live normal, healthy lives.
But men with Klinefelter syndrome are at a slightly increased risk of developing other health problems, including:. These problems can usually be treated if they do occur and testosterone replacement therapy may help reduce the risk of some of them. 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. The extra genetic information may either be carried in every cell in the body or it may only affect some cells known as mosaic Klinefelter syndrome.
Klinefelter syndrome is not directly inherited — the additional X chromosome occurs as a result of either the mother's egg or the father's sperm having the extra X chromosome an equal chance of this happening in either , so after conception the chromosome pattern is XXY rather than XY.
Most boys aren't likely to have major health problems, but the condition can bring some other challenges later in life. Klinefelter syndrome puts males at greater risk of breast cancer, some other cancers , and some other diseases like type 2 diabetes, varicose veins and problems with blood vessels, problems with sexual function, and osteoporosis weak bones later in life. Most boys with Klinefelter syndrome can have sex when they become men, usually with the help of testosterone treatment. But problems with their testicles prevent them from making enough normal sperm to father children.
Most men with the condition are infertile and can't father a child the usual way. Options for becoming natural parents are limited, but fertility researchers are working on new treatments. By the time someone with Klinefelter syndrome is ready to become a dad, there may be new options available related to saving sperm from the testicles.
Since Klinefelter syndrome can be hard to notice, many parents don't know their son has it until he grows up or shows delays in puberty. Sometimes, parents who are worried about their son's development consult a doctor, and the diagnosis reveals Klinefelter syndrome. This can help, because the earlier a boy is diagnosed with Klinefelter syndrome, the more effective the treatments usually are.
To diagnose Klinefelter syndrome, doctors usually begin by asking about any learning or behavior issues and examining the boy's testicles and body proportions.
They'll check a blood sample for the extra X chromosome. Before birth, the condition may be found through chromosomal analysis or noninvasive prenatal testing NIPT.
NIPT is done on the fluid surrounding the fetus, tissue from the placenta, or the blood from the mother. After birth, doctors can make a diagnosis with a chromosome karyotype test or microarray test from the baby. Doctors also can do hormone testing, usually by taking a blood sample to check for unusual hormone levels.
There's no way to change the XXY condition if a boy is born with it, but treatments can help relieve some symptoms. As with many conditions, beginning treatment early can make it much more effective. For older mothers, the risk is higher but only slightly.
A number of complications caused by Klinefelter syndrome are related to low testosterone hypogonadism. Testosterone replacement therapy reduces the risk of certain health problems, especially when therapy is started at the beginning of puberty. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version.
This content does not have an Arabic version. Overview Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the X chromosome.
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