Feature Article

Klinefelter’s syndrome: the most overlooked cause of androgen deficiency

Bianca St John, Rob McLachlan



Klinefelter’s syndrome (KS) 47,XXY, the most common cause of noniatrogenic hypogonadism in men, is associated with significant morbidity, mortality and psychosocial disadvantage yet most cases escape detection lifelong. Because early diagnosis may improve patient outcomes, doctors should consider KS in children with speech or motor delay, learning disabilities or psychobehavioural problems; in adults a simple testicular examination will ensure this important syndrome is not overlooked.

Key Points

  • Klinefelter’s syndrome (KS) 47,XXY is the most common numerical chromosomal disorder in males, yet most cases escape detection lifelong.
  • KS is most often diagnosed in adult men presenting with infertility or symptomatic androgen deficiency. Incidental detection occurs also during prenatal testing, but boys with KS often remain undiagnosed during childhood and adolescence, when physical signs can be subtle.
  • The invariant clinical feature of KS is progressive primary testicular failure, which is evident from early puberty.
  • In addition to androgen deficiency and infertility, KS is associated with a range of comorbidities and psychosocial issues.
  • From puberty, testosterone supplementation is recommended to ensure patients undergo full and timely virilisation and to prevent deleterious consequences of testosterone deficiency.
  • New management options for infertility are providing men with KS with a chance to father their own children via assisted reproduction.

    Picture credit: © GUSTOIMAGES/SPL/Diomedia.com. Model used for illustrative purposes only.