title: Klinefelter's syndrome: historical background and development.
abstract: When described more than 40 years ago, Klinefelter's syndrome (small testes, sterility, increased excretion of follicle-stimulating hormone, and usually gynecomastia) was thought to be an endocrine disorder. A second testicular hormone was postulated but has never been isolated. During the ensuing years, the syndrome has been found to be a chromosomal disorder, in which there is an extra X chromosome in 80% of the patients. The disorder occurs once in 500 to 1,000 male births and is best diagnosed by a buccal smear. When there is androgen deficiency, it is treated with testosterone. Gynecomastia is treated surgically because of the potential danger of malignancy or for cosmetic reasons.
mesh_terms: D000293:Adolescent; D000328:Adult; D001940:Breast / Q000601:surgery; D005260:Female; D049673:History, 20th Century; D006801:Humans; D007713:Klinefelter Syndrome / Q000235:genetics / Q000266:history*; D008297:Male; D012728:Sex Chromatin / Q000032:analysis; D013737:Testis / Q000473:pathology; D014481:United States