Klinefelter's Syndrome in Adolescent

A doctor may suspect Klinefelter's Syndrome when a boy reaches puberty if he has:

  • Undeveloped testes.
  • Delayed onset of puberty.
  • A high-pitched voice.
  • A sparse beard and sparse body hair.
  • Gynecomastia (enlarged breasts).
  • Feminine fat distribution.
  • Taurodontism (enlarged molar teeth).
  • Breast cancer or germ cell tumors from elevated estradiol.

If your doctor suspects your son has the androgen deficiency that accompanies Klinefelter's Syndrome, he will likely order the following blood tests to determine levels of:

  • FSH (follicle stimulating hormone).
  • LH (luteinizing hormone).
  • Oestradiol.
  • Testosterone.

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

KS and Infertility: There have been very recent break-through techniques in assisted reproductive therapies (ART) which have allowed some KS men to father their own biological children.
KS adolescents and men should see a reproductive endocrinologist for a detailed fertility assessment.

See your doctor. This is the critical time for medical investigation.

Download the Understanding Klinefelter Syndrome booklet

See your doctor