Klinefelter Syndrome Genetic Carrier Testing 

By  Staff Writer

Klinefelter syndrome Genetic Carrier Testing
In one out of 500 to 1,000 male births, the infant will have an extra X chromosome. This condition is known as Klinefelter syndrome. This genetic disorder cannot be cured, but it does not prevent boys and men from leading full, meaningful lives.

About Klinefelter Syndrome

A normal human has 46 chromosomes. Of these chromosome, two determine the person’s gender. Women have two X chromosomes, which is expressed as XX, while males have one X chromosome and one Y chromosome, which is noted with XY. However, sometimes some of the cells in the male body have an additional X chromosome. This is often written as XXY, though other variations may occur.

The extra sex chromosome appears because of an error in the formation of either the sperm or the egg. Some cases are so mild that they go undetected for many years. Others become clear at the onset of puberty.

Dr. Harry Klinefelter first published his studies regarding this condition in 1942. He worked with a group of nine men who all exhibited symptoms like small testes, enlarged breasts and sparse facial and body hair. Most tellingly, all of the subjects were unable to produce sperm. Research continued through the 1950s when the presence of the extra X chromosome was discovered. The extra chromosome is recognized as one of the most common genetic defects. However, not every male who has the extra chromosome actually exhibits the symptoms of Klinefelter syndrome.

Symptoms of Klinefelter Syndrome

Many boys are diagnosed with the syndrome after encountering learning problems at school. Alternatively, others are diagnosed when they reach the age when puberty should be well advanced yet show few outward signs. Symptoms like enlarged breasts, small testes and a smaller than usual penis are all common. Sparse facial and body hair and an unusually tall stature with disproportionate limbs may be other signs.

Males with Klinefelter syndrome often have low sperm count or are infertile. They are at an increased risk for breast cancer when compared with other men and may also be more likely to develop osteoporosis and lung disease. After a diagnosis, men must also be more aware that they are at risk for lupus and rheumatoid arthritis.

Klinefelter Syndrome Carrier Testing

This syndrome may be a genetic disorder, but it is not passed down through families. Accordingly, a baby or young boy may be diagnosed with the condition even if there is no family history. Some of these babies are identified before birth when doctors examine fetal cells obtained through amniocentesis or from a sample of the placenta. They may do this if the mother is older than 35 or if there is a history of other genetic disorders in the family. Alternatively, hormone testing or chromosome analysis after birth may also provide a definitive diagnosis.

No carrier test for Klinefelter syndrome exists. This is because the condition develops through unequal division in the sperm or the egg. Accordingly, it is not possible to detect a propensity for this condition until fetal cells can be examined. A chromosome analysis can be performed after birth, and this is often performed when it appears that puberty is not progressing normally. Adult males may opt for hormone testing and other tests to determine the presence of this disorder.

Babies, children and men with Klinefelter syndrome can lead long, normal lives. The typical treatment involves administering testosterone. When the treatment begins during the adolescent years, this helps the boy to develop more in accordance with his peers. Treatment continues throughout life, but cannot correct infertility.

Ask DNAcarriertests.com for more information about testing for Klinefelter syndrome.

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