There are 23 pairs of chromosomes found in each cell of the body, and each contain 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 individuals, 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 chromosome variations. The XXY variation is identified in an individual through a karyotype, a buccal smear, or FISH.
History
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 individuals who had similar features:
- tall (around six feet)
- small testes or hypogonadism
- inability to produce sperm
- sparse facial and body hair
- gynecomastia
XXY or Klinefelter syndrome?
Subsequent research
studies expanded and revised the original features 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
-
Other conditions which can be confused with Klinefelter syndrome.
Treatment
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 their 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
HRT has also been associated with elevated levels of cholesterol and red blood cells, and these must be carefully monitored.
Sexuality and Fertility
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.
Chromosomal Variations
Occasionally, variations of the XXY chromosome count may occur; the
most common being the XY mosaic. In this variation, some of the
cells are XXY and the rest are XY. The majority of these
individuals have similar outcomes as those who are XXY and require the
same treatment. There are reports of a slightly increased
likelihood of fertility for these men.
A few instances of males having two or even three additional X or Y
chromosomes (XXXY, XXXXY, XXYY, for example) 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 information about the benefits of early intervention
are less available. Though there is little hard research available,
there is also no indication that treatment would be any different for
those with these variations than for XXYs.
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 child and best meet his
evolving and individual needs. Parents are encouraged to relax
and enjoy their children as they would any other and to appreciate
their uniqueness and the many gifts they bring to this world.
Adolescence
Usually, XXYs enter puberty normally without any delay of physical
maturity. However, they fail to keep up with their peers 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 XXYs, 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 XXY penis 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 moods, 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, or a member of
your family, have been recently diagnosed it is
important to remember that while there may be challenges, 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 child. Begin now to seek out the
medical and psychological treatment and support network needed for the
individual.
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 are intended solely for the
information of the reader. They should not be used for
treatment purposes, but rather for discussion with the
patient's own physician.