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Klinefelter Syndrome

🩺 Nursing & Health By CampusDown Wiki Editorial Team Last updated
Quick answer: Klinefelter syndrome is a sex chromosome condition in which a male has an extra X chromosome (47,XXY), leading to reduced testicular function, low testosterone and usually infertility.
Contents
  1. 1. Cause
  2. 2. Symptoms
  3. 3. Diagnosis and treatment
  4. 4. References

Cause

Harry Klinefelter described the syndrome in 1942, and Jacobs and Strong identified the 47,XXY karyotype in 1959. It results from nondisjunction of sex chromosomes during parental meiosis and is usually not inherited.

Symptoms

  • Small firm testes, low testosterone and reduced sperm production causing infertility.
  • Tall stature with long limbs; breast development or reduced body hair may appear at puberty.
  • Intelligence is usually normal, but speech delay, reading and learning difficulties and attention problems can occur.
  • Higher risk of osteoporosis, metabolic syndrome and autoimmune disease.

Diagnosis and treatment

Many cases are found only in adulthood during fertility testing. A karyotype confirms the diagnosis. Testosterone therapy from puberty supports secondary sex characteristics and bone health, testicular sperm extraction with assisted reproduction can allow biological fatherhood, and speech and learning support help in school.

References

  1. Groth, K. A., Skakkebæk, A., Høst, C., Gravholt, C. H., & Bojesen, A. (2013). Klinefelter syndrome: A clinical update. Journal of Clinical Endocrinology & Metabolism, 98(1), 20-30.
  2. Klinefelter, H. F., Reifenstein, E. C., & Albright, F. (1942). Syndrome characterized by gynecomastia, aspermatogenesis without A-Leydigism, and increased excretion of follicle-stimulating hormone. Journal of Clinical Endocrinology, 2(11), 615-627.
  3. Jacobs, P. A., & Strong, J. A. (1959). A case of human intersexuality having a possible XXY sex-determining mechanism. Nature, 183, 302-303.

Reports and materials that use this theory (Korean)

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This article was last updated on October 15, 2026. It is based on widely recognized original works and textbooks; when citing it in a paper, please check the original sources listed in the references.