• Boys and men are born with an extra X chromosome
  • Common genetic condition affecting males
  • Often isn’t diagnosed until adulthood


  • Symptoms vary by age

In babies:

  • Weak muscles
  • Slow motor development
  • Delay in speaking
  • Quiet, docile personality

In boys and teenagers:

  • Taller than average stature
  • Longer legs, shorter torso and broader hips
  • Small, firm testicles
  • Small penis
  • Enlarged breast tissue
  • low energy levels
  • Tendency to be shy and sensitive
  • Difficulty expressing thoughts and feelings

In men:

  • Low sperm count or no sperm
  • Low sex drive
  • Taller than average height
  • Increased belly fat
  • Decreased facial and body hair


  • Presence of an extra X chromosome in males
  • The genetic material in the egg splits unevenly
  • Not inherited

Risk Factors

  • If the mother is over 35 years of age
  • For older mothers, the risk is higher but only slightly

Diagnostic Tests

  • Thorough physical exam
  • Hormone testing
  • Chromosome Analysis (Karyotyping)


  • Testosterone replacement therapy
  • Speech and language therapy during childhood
  • Educational and behavioural support
  • Fertility treatment
  • Breast tissue removal
  • Psychological counseling

Lifestyle Management

  • Learn about Klinefelter syndrome
  • Manage the patients development carefully
  • Keep regular follow-up appointments with medical professionals
  • Encourage participation in sports and physical activities
  • Encourage social opportunities and participation in group activities
  • Join support groups
  • Talk with others who have the condition
  • Work closely with the doctor