The following information was compiled and put into written format by Carol Wilson and Vaughn Hambley.
There are 23 pairs of chromosomes found in each cell of the body, and each contains genes that determine our coloring, our features, and our sex. Women inherit two X chromosomes -- one from each parent, written 46,XX. Men inherit an X chromosome from their mothers and a Y chromosome from their fathers, written 46,XY.
Some males, however, have an additional X chromosome in
their chromosomal arrangement, referred to as 47,XXY, or more
commonly, just XXY. The cause is unknown, yet XXY occurs in approximately 1 in every 500 to 1000 live male births, making it one of the most common chromosomal
anomalies. The XXY anomaly is identified in an individual through a karyotype.
Your physician may have referred to this genetic condition as either XXY or Klinefelter syndrome. Though these terms are often used interchangeably, they actually refer to two quite different, though related, conditions. In 1942, Dr. Harry
Klinefelter while working at the Massachusetts General
Hospital in Boston published with fellow researchers a report about nine adult males who had similar features:
- tall (around six feet)
- small testes or hypogonadism
- inability to produce sperm
- sparse facial and body hair
- gynecomastia
By the late 1950's researchers discovered that men with these features
(Klinefelter syndrome), had an extra X sex chromosome, and were XXY instead of
the typical male arrangement of XY.
XXY or Klinefelter syndrome?
Subsequent research studies expanded and revised the original symptoms to include the following as possible associated conditions:
- infertility
- incomplete masculinization; feminine, or pear shaped, body and body hair distribution
- decreased libido
- osteoporosis
- taurodontism
- venous disease
- learning, emotional, and mental disorders
- autoimmune disorders such as lupus
- low energy
- low self esteem
- communication difficulties, especially with expressive language
- frustration-based outbursts
- motor skill issues
- developmental delays
Some researchers list all of these as being Klinefelter syndrome. However, there is a trend among modern practitioners to distinguish chromosomal anomalies from any possible resulting syndromes, diseases, and conditions. It is important to remember that not all XXYs will develop any or all of these conditions. Since your extra X is just one out of 47, you have a lot of other genetic material that affects you in a variety of ways, and the extra X can differ in genetic coding from individual to individual.
Due in part to the lack of research and in part to the large variability of symptoms and characteristics, there is no one formula or treatment regime that is correct for every XXY. As a consequence, each XXY must assume responsibility for his own health care and advocate to be treated as an individual until the appropriate formula and treatment regime is ascertained.
Finding your proper care begins with identifying the health care professionals who will work with you toward that goal. XXYs will most likely be treated by an endocrinologist, a medical specialist who treats the endocrine (hormone producing) glands.
For the XXY, the key levels to be checked and monitored are the luteinizing hormone (LH) and testosterone. The luteinizing hormone is a substance produced by the pituitary gland that tells the testes to produce testosterone. When the testes of the XXY cannot carry out this function, more LH is secreted, raising that level. For most XXYs, testosterone levels are low-normal and below normal. Elevated levels of LH are indicative of insufficient testosterone for the individual.
Typically, Hormone Replacement Therapy (HRT) for XXYs involves testosterone treatment to mimic the natural testosterone cycles of a male as closely as possible and to balance this system.
Methods of delivery include:
- intramuscular injections
- skin patches
- gels
- implanted pellets
- oral pills
The most effective methods are the patch and injections.
HRT has also been associated with elevated levels of cholesterol and red blood cells, and these must be carefully monitored.
Adult XXYs are usually capable of normal erection and ejaculation. Though not able to manufacture enough sperm to father children, you should not automatically assume infertility without further testing. In a very small number of cases, XXYs have been able to father children. There are also sophisticated, though costly, methods of reproductive technology that may allow an XXY to biologically father a child. In any event, it is important that you consult with a fertility expert.
Related Chromosomal Variations
Occasionally, variations of the XXY chromosome count may occur; the most common being the XY/XXY mosaic. In this variation, some of the cells are XXY and the rest are XY. A few instances of males having two or even three additional X chromosomes have also been reported in the medical literature. Although research is even more sparse with respect to these numerous chromosomal variations, it is believed that these individuals may exhibit moderate to severe cognitive impairment, and experiences concerning the benefits of early intervention are less available.
Especially for Parents of an XXY Child
"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 and the director of the NICHD-sponsored study of XXYs. "Presumably, some of them will grow up to develop the syndrome Dr. Klinefelter described, but a lot of them won't."
Given this hopeful prospect, a good pediatrician is likely to be a parent's best guide in helping to raise an XXY son and best meet his evolving and individual needs. Parents are encouraged to relax and enjoy their son as they would any other child and appreciate his uniqueness and abilities.
Adolescence
Usually, XXY boys enter puberty normally without any delay of physical maturity. However, they fail to keep up with other males as puberty progresses. In teenage XY boys, the testes gradually increase in size from an initial volume of about 2 ml to about 15
ml. In XXY boys, the testes remain at 2 ml and cannot produce sufficient quantities of the male hormone testosterone. As a result, many XXY
adolescents may tire easily and lack muscle mass, facial or body hair, and
other secondary male characteristics. The penis of XXY boys is usually of
normal size.
XXY boys should begin testosterone treatment as they enter puberty. A regular schedule of HRT should promote the development of secondary male characteristics in the XXY. Improved self-confidence, increased
energy, more stable mood lability, decreased need for excessive sleep, enhanced
concentration, and improved social skills are also reported benefits of
testosterone treatment.
Once again, we must emphasize the needs of the individual and the importance of seeking out a good physician who is either knowledgeable about XXY or is willing to learn with you and to explore possibilities.
In Conclusion
If you have just learned that you or your son is an XXY, it is important to remember that while there may be challenges to overcome, the condition is far from being hopeless. With good information, support, and a knowledgeable medical provider who is willing to work with you or your son, any condition that may be associated with the presence of an extra X chromosome can today be addressed. Accordingly, take responsibility for your own health care and learn all you can about how being an XXY affects you or your son. Begin now to seek out the medical and psychological treatment and support network needed for the individual.
© 1999
Vaughn Hambley
Carol Wilson
This document was prepared using information available in relevant publications and research. Sources most widely consulted include: Robert Bock, "Understanding Klinefelter syndrome: A Guide for XXY Males and Their Families" and the work of Johannes Nielsen.
Disclaimer: The information and reference materials
contained herein is intended solely for the
information of the reader. It should not be used for
treatment purposes, but rather for discussion with the
patient's own physician.
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