Skip to main content

Klinefelter Syndrome

Lima Lawrence, MD Reviewed 06/2019
 


BASICS

DESCRIPTION

  • Most common congenital anomaly causing primary hypogonadism

  • Additional X chromosome in males, with most common karyotype 47,XXY (80–90%)

  • Causes cognitive, social, behavioral, and learn...

DIAGNOSIS

HISTORY

  • Prenatal testing (10%)

  • Newborn: hypotonia, genital abnormalities

  • Adolescence: delayed or absent puberty, persistent gynecomastia, small testes, learning disabilities, psychosocial probl...

TREATMENT

GENERAL MEASURES

  • Preventive dental care

  • Calcium and vitamin D supplementation

MEDICATION

First Line

Testosterone replacement therapy 
  • Benefits

    • Develops secondary male sex characteristics

      • Increas...

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Patient Monitoring

  • Metabolic screening every 3 months and then annually: lipids, glucose, and thyroid function

  • Annual clinical breast exam ± breast imaging

  • Bone dens...

REFERENCES

1
Aksglaede L, Link K, Giwercman A, et al. 47,XXY Klinefelter syndrome: clinical characteristics and age-specific recommendations for medical management. Am J Med Genet C Semin Med Genet. &#...

ADDITIONAL READING

  • Davis S, Howell S, Wilson R, et al. Advances in the interdisciplinary care of children with Klinefelter syndrome. Adv Pediatr.  2016;63(1):15–46. [View Abstract on OvidMedline]

  • ...

CODES

ICD10

  • Q98.4 Klinefelter syndrome, unspecified

  • Q98.1 Klinefelter syndrome, male with more than two X chromosomes

  • Q98.0 Klinefelter syndrome karyotype 47, XXY

  • Q98.5 Karyotype 47, XYY

  • Q98.3 Other male w...

CLINICAL PEARLS

  • KS males have ≥1 additional X chromosome (XXY karyotype) with associated features of hypergonadotropic hypogonadism.

  • Accounts for 3% of male infertility

  • Most men do not have “textbook fe...

Subscribe to Access Full Content

Sign Up for a 10-Day Free Trial

Sign up for a 10-day FREE Trial now and receive full access to all content.

 
×