Chromosomal defect in males in which there is an extra x chromosome. Manifestations may include underdeveloped testes, physical feminization, sterility, and intellectual disability.
An abnormality affecting males in which the sex-determining chromosomes are XXY instead of the normal XY. One gamete some-how contributes an extra X chromosome at the time of fertilization. Symptoms include small testicles, sterility, and, frequently, feminine physical features.
A genetic disorder in which a male has an extra female chromosome, making an XXY set, giving sterility and partial female characteristics.
Klinefelter syndrome (KS) results from a chromosomal abnormality in which at least one extra X chromosome is present in males. Obvious signs of KS often do not appear until adolescence or adulthood, when males with KS often show hypogonadism, delayed puberty, and excessive growth of lower extremities. Although the chromosomal abnormality can be diagnosed in infancy or childhood, it is most often diagnosed in adulthood when questions of fertility arise.
A congenital condition resulting from a chromosomal abnormality, in which a male has not just the usual two sex chromosomes (XY), but one or more additional X chromosomes. Males with one extra X chromosome (labeled 47,XXY) are often tall and lean, with some tendency to learning disabilities in the verbal area; in many, the syndrome is recognized only during a search for causes of infertility, since most lack sperm. Even for those with two or more additional X chromosomes, Klinefelter’s syndrome generally shows itself only at puberty, when such males tend to develop enlarged breasts (gynecomastia) and other secondary sex characteristics that tend toward the female, though these can sometimes be modified surgically or through hormone treatment. The testes, however, remain small, giving the syndrome an alternate name, primary micro-orchidism. People with Klinefelter’s syndrome are somewhat more likely than most to have some mental retardation and difficulty in social adaptation.
Defect in which at least one extra X chromosome (XXY) is present in a male (normally XY) and that is characterized by small testes, enlarged breasts, long legs, decreased or absent sperm production, and mental retardation. Persons with more than one extra X (e.g., XXXY) usually show marked physical and mental abnormalities.
A chromosome abnormality affecting only men due to the presence of an extra X chromosome. Klinefelter syndrome causes hypogonadism (inadequate function of the sex glands that results in decreased production of sex hormones) and infertility. An infant with Klinefelter syndrome appears normal at birth, but during puberty the secondary sexual characteristics fail to develop, at which point the problem becomes apparent, Testicular abnormalities result in infertility in most cases. Symptoms and associated conditions may include a small penis and small firm testicles; diminished pubic, facial, and body hair; sexual dysfunction; enlarged breast tissue (gynecomastia), tall stature, long legs and short trunk; learning disabilities; and emotional disorders. In some mild cases there may be few signs, except for infertility.
A genetic disorder in which there are three sex chromosomes, XXY, rather than the normal XX or XY. Affected individuals are apparently male, but are tall and thin, with small testes, failure of normal sperm production (azoospermia), enlargement of the breasts (gynecomastia), and absence of facial and body hair.
The original syndrome described by Klinefelter consisted of gynaecomastia, testicular atrophy and infertility. Intelligence was unimpaired. Some patients have associated learning disability and striking tallness of stature, but the only constant feature of the syndrome is testicular atrophy with resulting lack of production of spermatozoa and subsequent infertility. A small penis, loss of body hair and a highpitched voice may be present.
The most common sex chromosome syndrome, marked by primary testicular failure. The classic form is associated with the presence of an extra X chromosome. Affected persons have small, firm testes, gynecomastia, abnormally long legs, minimal body and facial hair, and infertility. In variant forms the chromosomal abnormalities vary and the severity and number of abnormal findings are diversified. The syndrome is estimated to occur in one of 500 live male births. Diagnosis may be confirmed by chromosomal analysis of tissue culture, which usually demonstrates a 47, XXY genotype.
Klinefelter syndrome is a medical condition caused by the presence of additional X chromosomes in males, leading to smaller testes, infertility, heightened stature, reduced facial hair, and occasionally breast enlargement.
A chromosomal irregularity occurs when a male possesses an additional X chromosome in his cells, resulting in an XXY configuration instead of the typical XY. The likelihood of a baby having this condition rises with the mother’s age.
Symptoms of the syndrome can vary and might not be noticeable until the child hits puberty. At that point, breast enlargement (gynaecomastia) can develop, and the testes typically stay undersized. Most affected males are often infertile. They usually have a tall and slender physique resembling a female body contour and lack body hair. Those with Klinefelter’s syndrome also have a higher likelihood of facing learning challenges compared to the general populace.
While there isn’t a cure, hormonal treatments can prompt puberty-related changes like facial hair growth, and surgical procedures can address breast enlargement (gynaecomastia).