|... caused by a chromasomal abnormality in which males have an extra X chromosome ... constellation of symptoms ... tall stature, small testes (microorchidism), sparse facial and body hair, enlarged breast tissue (gynecomastia), and greatly reduced sperm count ... delays ... motor skills and language development ... indistinguishable from other boys until puberty ... Testosterone replacement treatment ... should begin around 11 years of age ... Fertility counseling ... in Denmark ... 71% of prenatally identified Klinefelter syndrome were aborted ...
Klinefelter syndrome and other sex chromosomal aneuploidies
Jeannie Visootsak and John M Graham Jr, Orphanet Journal of Rare Diseases, October 24, 2006
[for Professionals mainly]
The term Klinefelter syndrome (KS) describes a group of chromosomal disorder in which there is at least one extra X chromosome to a normal male karyotype, 46,XY. XXY ... most common disorder of sex chromosomes in humans ... one in 500 males ... 46,XX males also exist and it is caused by translocation of Y material including sex determining region (SRY) to the X chromosome during paternal meiosis ... 47,XXY males may present with a variety of subtle clinical signs that are age-related ... may have ... hypospadias, small phallus or cryptorchidism, developmental delay ... language delay, learning disabilities, or behavioral problems ... delayed or incomplete pubertal development with eunuchoid body habitus, gynecomastia, and small testes. Adults are often evaluated for infertility or breast malignancy ... replacement therapy should begin at puberty, around age 12 years ... Affected individuals have longer arms and legs ... Testicular volume is typically less than 10 ml in postpubertal 47,XXY individuals ... most patients with Klinefelter syndrome are infertile ... few patients with reports of pregnancy without assisted medical technology ... 69% (29 of 42 men) had adequate sperm found using intracytoplasmic sperm injection ... wide range of intelligence quotient (IQ) has been noted ... breast carcinoma in 47,XXY is relatively increased ... Associated endocrine complications include diabetes mellitus, hypothyroidism, and hypoparathyrodism ... lupus erythematosus, Sjogren syndrome, and rheumatoid arthritis, are more common ... with frequencies similar to those found in 46,XX females ... Development of varicose veins and leg ulcers may result from venous stasis ... recurrence risk is not increased above that of the general population ...
Understanding Klinefelter Syndrome A guide for XXY Males and their families
Robert Bock Office of Research Reporting, NICHD - August 1993.
[for Professionals mainly] [Support Group] "... comprehensive site ..."
What is Klinefelter Syndrome?
Detecting Language Problems Early
In 1942, Dr. Harry Klinefelter and his coworkers at the Massachusetts General Hospital in Boston published a report about nine men who had enlarged breasts, sparse facial and body hair, small testes, and an inability to produce sperm
"I never refer to newborn babies as having Klinefelter's, because they don't have a syndrome," said Arthur Robinson, M.D., a pediatrician at the University of Colorado Medical School in Denver
"Presumably, some of them will grow up to develop the syndrome Dr. Klinefelter described, but a lot of them won't."
the term "Klinefelter syndrome" has fallen out of favor with medical researchers. Most prefer to describe men and boys having the extra chromosome as "XXY males."
often don't appear any different from anyone else, many XXY males probably never learn of their extra chromosome
a few XXY males are diagnosed at adolescence, when excessive breast development forces them to seek medical attention
When the truth is withheld, children often suspect that their parents are hiding something
This school of thought maintains that by the time he is 10 or 11 years old, the child can be told that his cells differ slightly from those of other people
By roughly the age of 12, depending on the child's emotional maturity, he can be told that he will most probably be infertile
other experts believe that holding back the information does not appear to do any harm. Instead, telling an XXY boy about his extra chromosome too early may have some unpleasant consequences. An 11 or 12-year-old, for example, may associate infertility with sexual disorders and other concepts he may not yet understand
children, when making friends, tend to share secrets
confidences are sometimes betrayed. A malicious or thoughtless child may tell all the neighborhood children that his former companion is a "freak"
In some, the language delays may be more severe
Detecting Language Problems Early
If their son's speech seems to be lagging behind that of other children, parents should ask their child'' pediatrician for a referral to a speech pathologist for further testing
pay particular attention to their children's hearing
XXY males often have decreased immediate auditory recall
Parents and teachers can help them remember by approaching memory through visual channels
Research indicates that XXY boys may do poorly in an open classroom situation and seem to prefer a structured, tightly organized environment centered around familiar routines
they fail to keep pace with other males
only about 10 percent of XXY males have breast enlargement great enough to require surgery
males should begin testosterone treatment as they enter puberty
testosterone injections often bring on psychological changes as
As a group, XXY boys tend to suffer from depression, principally because of their scholastic difficulties and problems fitting in with other males their age. Sudden, angry changes in mood are typical of depressed people
there is no evidence that XXY males are any more inclined toward homosexuality than are other men
XXY males may have less interest in sex
The vast majority of XXY males do not produce enough sperm to allow them to become fathers
However, no XXY male should automatically assume he is infertile without further testing. In a very small number of cases, XXY males have been able to father children
XXY males have a slightly increased risk of autoimmune disorders
XXY males with enlarged breasts have the same risk of breast cancer as do women-roughly 50 times the risk XY males have
Learning About Klinefelter Syndrome
National Human Genome Research Institute, December 2006
"... reliable source ... up-to-date information ..."
National Institute of Child Health & Human Development, May 24, 2007
"... very detailed, current information ... free booklet ... "
National Library of Medicine, June 14, 2007
"... links to journal articles ..."
Cytogenetics Lab, July 1999
A variant of Klinefelter's syndrome
are male, typically with
Klinefelter Syndrome and Associates
Klinefelter Syndrome and Associates, Inc., May 21, 2007
Klinefelter Syndrome and Associates is a non-profit education and support organization for the genetic condition Klinefelter Syndrome (XXY) and its variants. You'll be amazed at the wealth of information provided here on this very common, but under-diagnosed condition
Clinical sign of: Klinefelter syndrome
abn. dermatoglyphics excl. simian crease
chromosomal anomalie (number)
clinodactyly of fifth finger
mental retardation (mild)
Deutsche Klinefelter-Syndrom Vereinigung
[Support Group] [Geman]
Signe clinique de: Klinefelter syndrome
clinodactylie due 5eme doigt
dermatoglyphes anormaux (autre que ppt)
gynecomastie/glande mammaire hyperplasie
hyperglycemie/diabete non ins. dep.
pli palmaire transverse
retard mental modere/leger
trisomie ou monosomie totale/partielle
troubles du comportement
I.B.I.S. Birth Defects, 2002
History ... What is Klinefelter syndrome ... Cause ... Diagnosis ... Advices to patients, thier families and friends ... Childhood ... Early detection of speaking problems ... Advices concerning studying at school ... Juvenile age ... Testosterone treatment ... Chromosome variations ... Sexuality ... Infertility ... Adult age
Last Updated: 2008/06/10