Klinefelter et al. first reported the first case of male sexually transmitted disease in 1942. Jacobs et al. discovered in 1959 that such patients have one more X chromosome than normal males, hence this is a chromosomal aberration disorder. The disease cause is the non-disjunction of the X chromosome during meiosis in diploid sperm or egg cells, resulting in sperm or eggs with an extra X chromosome. Most of these patients are taller in stature, exhibit a eunuchoid body type, have fine and pale skin, sparse pubic and facial hair, and often lack underarm hair. Some cases present with bilateral breast hypertrophy, external genitalia resembling normal males but with a short penis, significantly smaller and firm testes on both sides, poor sexual function, and aspermia in the semen. The intelligence of such individuals is somewhat lower than that of normal people.

bubble_chart Clinical Manifestations

Patients with this syndrome exhibit low testosterone levels in blood and urine, while gonadotropins are significantly elevated. Pathological examination of the testes reveals the following two types of lesions: (1) Thickening of the basement membrane of the seminiferous tubules, showing hyaline degeneration, absence of elastic fibers, and aspermia in the tubular lumen. In severe cases, the seminiferous tubules may become completely fibrotic. (2) Marked hyperplasia of interstitial cells. The patients test positive for X chromatin, and the typical karyotype is 47,XXY, though some variants exist, such as 48,XXXY and 49,XXXXY. Generally, the greater the number of X chromosomes, the more severe the intellectual disability, sometimes accompanied by malformations such as cleft palate, cryptorchidism, and torticollis. Another subset comprises sex mosaics, commonly 46,XY/47,XXY. Patients with a 46,XXY cell line exhibit milder signs and testicular lesions compared to those with 47,XXXY.

bubble_chart Treatment Measures

For the treatment of this disease, male hormones are generally used to improve the patient's secondary sexual characteristics, but the efficacy is usually not very satisfactory. Male hormones can be administered as testosterone propionate 25mg intramuscularly 2-3 times a week, or methyltestosterone tablets 25-50mg daily. Some long-acting testosterone preparations can also be used, and human chorionic gonadotropin 2000U can be administered simultaneously twice a week. For patients with excessive development of both breasts, surgical removal may be performed.

Currently, the use of testosterone undecanoate 120mg/d, with a 12-week course, can achieve improvements in sexual function, increase testosterone hormone levels in hematuria, and reduce follicle-stimulating hormone and co-hormone levels.