When should I tell my son he has Klinefelter syndrome?

Experts recommend explaining to your affected child that he has Klinefelter syndrome when he reaches his mid-to-late teens. He should be old enough by then to understand its implications. Give him a copy of the booklet available at http://www.klinefeltersyndrome.us. Knowing that there is hope and that there are treatments that may help him to deal with his symptoms.

Adult Men
Most men with Klinefelter syndrome do not exhibit symptoms. You may first notice a problem when you experience:

• Lack of libido
• Sexual Dysfunction (SD)
• Infertility
• Varicose veins that tend to ulcerate or clot (thrombosis)
• Mitral valve prolapse
• Poor self-esteem
• Psychological distress

Klinefelter Facts

• Girls do not develop Klinefelter syndrome
• It does not occur more in one race than any other
• Klinefelter syndrome does not decrease the longevity of boys
• Most males with the syndrome are undiagnosed until adulthood, when they have reproductive problems
• Older mothers tend to produce more Klinefelter syndrome babies

What are the variants?

• 80%—90% of affected boys have 47,XXY (one additional X chromosome). Most boys with the 47,XXY karyotype have normal intelligence.
• 10% have mosaicism (46,XY/47,XXY). Men with Klinefelter syndrome mosaicism are often fertile and can father a child through modern technology.
• Very rare and more serious variants are 48,XXYY; 48,XXXY; 49,XXXYY; 49,XXXXY; 47,X,i(Xq)Y and 47,X,del(X)Y). Boys with these rare variants have mental retardation that increases with more X chromosomes.

Statistics

• Most males who are infertile and have small testicles (grape size) due to a chromosomal disorder have Klinefelter syndrome with a 47,XXY karyotype (extra X and Y chromosomes) or a variant.
• In Australia, 1 in 650 males is born with Klinefelter syndrome.
  
• In the U.S.A., 1 in 500—1,000 males has an extra sex chromosome.
  
• Klinefelter syndrome is dramatically underdiagnosed.
• If your healthcare practitioner is unfamiliar with the finer details of Klinefelter syndrome, there is a free booklet available at http://www.klinefeltersyndrome.us