Clinical features

Testosterone deficiency and unsuppressed follicle-stimulating and luteinizing hormones activity (directly or indirectly) is responsible for the most common phenotypic features seen in KS (1).

Characteristic clinical findings of a male with KS are as follows:

• infertility (azoospermia or oligospermia)
  • in mosaic cases, reports of pregnancy without assisted medical technology has been reported
• small, firm testes - in postpubertal patients the testicular volume is typically less than 10 ml
• gynecomastia - incidence of gynecomastia in KS may vary between 56% to 88%
• tall, slender body structure with long legs and shorter torso
• features of persistent androgen deficiency -
  • loss of libido
  • reduced beard growth and secondary body hair
  • decreased muscle bulk and tone
  • decreased bone mineral density
  • susceptibility for thromboembolism
  • an increased risk of mortality from diabetic and cardiovascular complications
• motor delay or dysfunction
• speech and language difficulties
• attention deficits
• dyslexia or reading dysfunction
• psychosocial or behavioral problems (2,3)

Reference:

• (1) Wattendorf DJ, Muenke M. Klinefelter syndrome. Am Fam Physician. 2005;72(11):2259-62.
• (2) Visootsak J, Graham JM Jr. Klinefelter syndrome and other sex chromosomal aneuploidies. Orphanet J Rare Dis. 2006;1:42.
• (3) Bojesen A, Gravholt CH. Klinefelter syndrome in clinical practice. Nat Clin Pract Urol. 2007;4(4):192-204.