Complications associated with Klinefelter's syndrome

• there is an increased risk of acquiring breast cancer in Klinefelter subjects, with relative risk exceeding 200 times more than in a normal individual. This may be due to high estradiol to testosterone ratio levels when compared to karyotypically normal men or due to an increased peripheral conversion of testosterone to estradiol
  
  
• endocrine complications includes:
  • diabetes mellitus
  • hypothyroidism
  • hypoparathyrodism
    
    
• autoimmune disease conditions are more commoner, such as :
  • SLE
  • sjogren syndrome.
  • rheumatoid arthritis
    
    
• venous stasis leading to varicose veins and leg ulcers
  
  
• decreased bone density - in almost 25% of patients with KS

Reference:

• (1) Visootsak J, Graham JM Jr. Klinefelter syndrome and other sex chromosomal aneuploidies. Orphanet J Rare Dis. 2006;1:42.