Klinefelter Syndrome

• Prevalence and genetics

  • Only found in males
  • 1 in 600-650 babies
  • Not inherited
  • Risk increases with parents' age at conception
  • Additional X chromosome in 23rd pair (XXY)
  • Two-thirds of those with Klinefelter's are unaware
• Physical characteristics

  • Reduced body hair
  • Hypogonadal - diminished functional activity of the gonads
  • Gynaecomastia - breast development in puberty
  • Lower muscle tone and strength
  • Reduced fertility
  • Increased risk of type 2 diabetes and breast cancer
  • Long gangly limbs
• Psychological characteristics


  • Poorly developed language skills and reading ability
  • Low mood and energy levels
  • Poor problem-solving skills
  • Low libido