Klinefelter Syndrome

Klinefelter syndrome is the most common sex-chromosome condition in males. Most affected people have a 47,XXY karyotype: the usual X and Y chromosomes plus one extra X. The extra X progressively damages the testes, producing primary (hypergonadotropic) hypogonadism: testosterone is low or low-normal while the pituitary raises luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in an attempt to drive failing testes. Published prevalence estimates differ by source. MedlinePlus Genetics reports about 1 in 650 male newborns. The Healthy Male clinical summary estimates about 1 in 500 males, with only around half ever diagnosed, and MedlinePlus states that up to 65% of affected people are never diagnosed. Under-diagnosis matters for nursing: many people reach adulthood without a diagnosis and present with infertility, small testes, breast enlargement or symptoms of low testosterone. The nursing picture changes with age. A child may have few physical signs but speech, reading or attention difficulties. An adolescent may have incomplete pubertal progression. An adult may present with infertility, small firm testes, gynecomastia, low energy, reduced libido, low bone density or metabolic problems. The RN assesses, teaches,...