Klinefelter syndrome

Klinefelter syndrome (Klinefelter–Reifenstein–Albright syndrome) is a genetic disorder in which an individual (male) has one Y chromosome and two or more X chromosomes (normally there is only one), i.e. 47,XXY; in some cases mosaic forms or other combinations may occur, such as the presence of three X chromosomes. The incidence in our region is approximately 0.2%.

Affected individuals usually exhibit male sexual characteristics but are infertile. Intelligence is typically not affected. Current treatment options do not allow for a cure of the disorder, but only symptomatic management. Individuals may therefore be asymptomatic.

Treatment

Administration of testosterone is the mainstay of treatment. These individuals have an increased risk of germ cell tumors of the testes, breast cancer, and osteoporosis. With appropriate treatment, men with this genetic condition can lead a full life comparable to that of healthy individuals.

• if a mosaic genetic defect is present (a portion of the body’s cells has a normal chromosomal composition – karyotype), the condition may be asymptomatic
• infertility
• hypogonadism (underdeveloped gonads)
• gynecomastia (enlargement of the male breast glands)
• penile size may not be affected
• testicular atrophy (reduction in size) with hyalinization of the seminiferous tubules (occlusion due to hyaline deposition)
• delayed puberty
• changes in body hair
• often tall, slender body habitus with eunuchoid features (lack of typical male characteristics)
• low serum testosterone levels, but elevated levels of follicle-stimulating hormone (FSH) and luteinizing hormone (hypergonadotropic hypogonadism)
• delayed speech development
• attention or behavioral disorders, learning difficulties