What is Klinefelter's Syndrome?

These are a number of websites that can help you understand Klinefelter's Syndrome. A simple search on Google can help find a number of these sites.

Also the website http:www.klinefeltersyndrome.us has available a downloadable booklet that describes Klinefelters in detail and has lots of other information on the site as well. Lots of good links to other organisations that can help.

Klinefelter syndrome is the most common cause of male infertility. It is a sex chromosome variation that occurs in 1 in 500 males (independent of ethnic origin). Most men do not demonstrate symptoms. Normally, males have one X chromosome in their cells. Males affected with Klinefelter syndrome have at least one extra X chromosome in most of their cells. The extra chromosome impacts their:

• Bone strength
• Energy level
• Hair growth
• Height
• Hip girth
• Language development
• Learning
• Muscle mass
• Social development
• Thought processes

Klinefelter syndrome is also known as XXY syndrome.

How can I detect it?

Babies and Toddlers
A geneticist can diagnose Klinefelter syndrome before your son is born through a fetal cytogenetic analysis.

Your pediatrician may suspect Klinefelter syndrome if your infant son 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 Klinefelter syndrome develop normal height and weight until they reach age 4 or 5. In 25% of boys, there is a telltale condition called clinodactyly, where the little finger curves toward the ring finger because the middle bone is wedge-shaped instead of rectangular.

School-age Boys
Your pediatrician may investigate your school-age son for Klinefelter 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 Black, epicanthal skin folds on his upper eyelids at the inner corner, giving him an oriental look
• 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

You may ask your pediatrician to investigate your son for Klinefelter syndrome if he has:

• Attention Deficit Disorder (ADD)
• Learning disability (especially dyslexia, reading difficulty, and 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

Puberty
Your doctor may suspect Klinefelter syndrome when your boy reaches puberty if he has:

• High-pitched voice
• Sparse beard and 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 syndrome, he will likely be sent to a lab for these blood tests:

• FSH (follicle stimulating hormone)
• LH (luteinizing hormone)
• Estradiol
• Testosterone (available worldwide at http://hormonesolutions.com.au)
  

You may ask your doctor to perform genetic screening for Klinefelter syndrome if your son exhibits:

• Inability to deal with stress
• Psychological problems, like anxiety, neurosis, depression, or psychosis