What is Kleinfelter's syndrome?

Question

Also, what causes it?

Answer 1

Klinefelter's syndrome is a genetic abnormality that affects only males. Named after an American physician, Harry Klinefelter in 1942, Klinefelter's syndrome affects approximately 1 per 1,000 males, making it a very common genetic abnormality.
Chromosomes are genetic material and a person's sex is determined by X and Y chromosomes. Males usually have one X and one Y chromosome (XY). Males with Klinefelter's syndrome have extra X chromosome (XXY).

Klinefelter's syndrome may be identified in adolecense when the testes do not develop when they should. Testosterone therapy can have a number of positive effects although most men with Klienfelter's are never able to father a child. However testosterone can improve sex drive, promote hair growth, increase muscle strength.

Answer 2

Kleinfelter's syndrome is a chromosomal disorder,in which male babies are born with a extra X chromosome.They have normal intelligence,but many have problems with speech and reading disabilities.They may have sparse facial hair,and small testes,and usually sterile.Take care. SW RNP

Answer 3

Klinefelter's syndrome — Klinefelter's syndrome is the most common congenital abnormality causing primary hypogonadism, occurring in approximately 1 in 1000 live male births [1,2]. This syndrome is the clinical manifestation of a male who has an extra X chromosome. The most common genotype is 47,XXY (show figure 1), but greater and lesser numbers of X chromosomes have also been reported, resulting in karyotypes such as 48 XXXY and 46,XY/46,XXY mosaicism [3]. 46,XX males also have Klinefelter's syndrome; the development of testes in this setting is presumably due to translocation of a small portion of chromosomal material containing the testis-determining factor to an X chromosome.

The 47,XXY genotype results from nondisjunction of the sex chromosomes of either parent during meiotic division, while mosaicism probably results from nondisjunction during mitotic division after conception. The greater the number of extra X chromosomes, the greater the phenotypic consequences, both gonadal and extragonadal [3]: Damage to the seminiferous tubules and, usually, damage to the Leydig cells as well. The gonadal manifestations include almost invariably small, firm testes, severely subnormal sperm count, infertility, elevated serum FSH and LH concentrations, variably subnormal serum testosterone concentration and decreased virilization [3,4]. A long bone abnormality, resulting in increased length of the legs, independent of the increased length of both the arms and legs caused by testosterone deficiency. A behavioral abnormality, unrelated to the hypogonadism, which causes difficulty in social interactions throughout life [5]. Predisposition to develop morbidities later in life that are unrelated to testosterone deficiency [6]. These include pulmonary diseases such as chronic bronchitis, bronchiectasis, and emphysema [7]; cancers, including germ cell tumors (particularly extragonadal tumors involving the mediastinum) [8], breast cancer [9], and possibly non-Hodgkin lymphoma [10]; varicose veins, leading to leg ulcers [11]; and diabetes mellitus [12]. (See "Extragonadal germ cell tumors involving the mediastinum and retroperitoneum" and see "Male breast cancer").

The phenotype in Klinefelter patients also appears to be modified by the length of the CAGn polymorphism of the androgen receptor gene (CAG repeat length correlates inversely with transactivational activity of the androgen receptor). As an example, in a study of 77 newly diagnosed and untreated Klinefelter patients (48 of whom were hypogonadal), longer CAGn length was associated with taller stature, lower bone mineral density, gynecomastia, and employment not requiring a high level of education [13]. In a similar study of 35 patients with Klinefelter syndrome, longer CAGn length was inversely correlated with penile length [14].

Diagnosis of Klinefelter's syndrome usually can be made by determining the karyotype of the peripheral leukocytes. Testosterone deficiency and the resulting hypogonadism, if present, can be treated with testosterone. (See "Testosterone treatment of male hypogonadism"). Hormone replacement is unlikely to improve the other abnormalities. Successful fertility has been achieved with assisted reproductive technologies in some cases, but there are important genetic implications of these procedures [15]. (See "Treatment of male infertility"). The physician should discuss the nature of the problem with the patient, his parents, and his teachers and counselors, and should also encourage them to contact a support group. There are two national groups, and they are associated with local groups:

  Klinefelter Syndrome and Associates
  P.O. Box 119
  Roseville, CA 95678
  916-773-2999
  genetic.org

  American Association for Klinefelter's Syndrome Information and Support
  www.aaksis.org
  888-466-5747

Answer 4

I know that it is when a child has an extra X chromosome (or maybe its an extra Y) chromozome.

Its a genetic abnormality that happens at the time fertilization of the egg occurs by the sperm.

its the luck of the draw.

Answer 5

XXY
genetic disorder.
must be male
1/4 of prison population is suspected of having it.