Klinefelter's Syndrome in Children

A geneticist can diagnose Klinefelter's Syndrome before your son is born through a foetal cytogenetic analysis.

A paediatrician may suspect Klinefelter's Syndrome if an infant boy has:

  • Developmental delay
  • Undescended testicles (cryptorchidism)
  • Pea-sized testicles
  • Hypospadias (urine dribbles out of an opening on the underside of his penis)

However, 75% of boys with KS develop normal height and weight until they reach age four or five.

A paediatrician may investigate a school-age boy for Klinefelter's Syndrome if he has this characteristic appearance:

  • Tall stature.
  • Knock-knees (genu valgum).
  • High arches (pes cavus).
  • Protruding lips.
  • Projecting jaw (prognathism).
  • Very widely-spaced eyes (hypertelorism).
  • If he is Caucasian or African American, epicanthal skin folds on his upper eyelids at the inner corner.
  • Poor coordination.
  • Fused bones in his forearms that make it difficult for him to rotate his arms (radioulnar synostosis).
  • Quiet, tractable personality with occasional tantrums and aggression.

Parents should ask a paediatrician or family doctor to investigate a boy for Klinefelter’s syndrome if he has:

  • Pea-size testicles.
  • Attention Deficit Hyperactivity Disorder (ADHD).
  • A learning disability (especially dyslexia, reading difficulties, and/or data retrieval problems).
  • Mental retardation (IQ drops 15 points for each additional X chromosome).
  • Poor expressive and receptive language skills.
  • Poor short term memory.
  • Osteoporosis (bone thinning).
  • Lack of sporting ability.

There are many variants of KS and not all KS children will exhibit or display some or all of the above signs and symptoms. A rare few may even have normal size testes, how it is important that if some of the above exist that your doctor exclude KS as a possible cause.

See your doctor

Two exceptional websites are the US National Institute of Child Health and Development and the Australasian Paediatric Endocrine Group.