Understanding Klinefelter Syndrome: A Guide
for XXY Males and Their Families
Office of Research Reporting, NICHD
What is Klinefelter Syndrome?
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
By the late 1950s, researchers discovered that men with Klinefelter syndrome,
as this group of symptoms came to be called, had an extra sex chromosome, XXY
instead of the usual male arrangement, XY. (For a more complete explanation of
the role this extra chromosome plays, see the accompanying section,
"Chromosomes and Klinefelter syndrome.")
In the early 1970s, researchers around the world sought to identify males
having the extra chromosome by screening large numbers of newborn babies. One of
the largest of these studies, sponsored by the National Institute of Child
Health and Human Development (NICHD), checked the chromosomes of more than
Based on these studies, the XXY chromosome arrangement appears to be one of
the most common genetic abnormalities known, occurring as frequently as 1 in 500
to 1 in 1,000 male births. Although the syndrome's cause, an extra sex
chromosome, is widespread, the syndrome itself-the set of symptoms and
characteristics that may result from having the extra chromosome-is uncommon.
Many men live out their lives without ever even suspecting that they have an
" 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 XXY males. "Presumably, some of them will grow up to develop the
syndrome Dr. Klinefelter described, but a lot of them won't."
For this reason, 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."
In addition to occasional breast enlargement, lack of facial and body hair,
and a rounded body type, XXY males are more likely than other males to be
overweight, and tend to be taller than their fathers and brothers.
For the most part, these symptoms are treatable. Surgery, when necessary, can
reduce breast size. Regular injections of the male hormone testosterone,
beginning at puberty, can promote strength and facial hair growth-as well as
bring about a more muscular body type.
A far more serious symptom, however, is one that is not always readily
apparent. Although they are not mentally retarded, most XXY males have some
degree of language impairment. As children, they often learn to speak much later
than do other children and may have difficulty learning to read and write. And
while they eventually do learn to speak and converse normally, the majority tend
to have some degree of difficulty with language throughout their lives. If
untreated, this language impairment can lead to school failure and its attendant
loss of self esteem.
Fortunately, however, this language disability usually can be compensated
for. Chances for success are greatest if begun in early childhood.
Chromosomes and Klinefelter Syndrome
Chromosomes, the spaghetti-like strands of hereditary material found in each
cell of the body, determine such characteristics as the color of our eyes and
hair, our height, and whether we are male or female.
Women usually inherit two X chromosomes-one from each parent. Men tend to
inherit an X chromosome from their mothers, and a Y chromosome from their
fathers. Most males with the syndrome Dr. Klinefelter described, however, have
an additional X chromosomes total of two X chromosomes and one Y chromosome.
No one knows what puts a couple at risk for conceiving an XXY child.
Advanced maternal age increases the risk for the XXY chromosome count, but only
slightly. Furthermore, recent studies conducted by NICHD grantee Terry Hassold,
a geneticist at Case Western Reserve University in Cleveland, OH, show that half
the time, the extra chromosome comes from the father.
Dr. Hassold explained that cells destined to become sperm or eggs undergo a
process known as meiosis. In this process, the 46 chromosomes in the cell
separate, ultimately producing two new cells having 23 chromosomes each. Before
meiosis is completed, however, chromosomes pair with their corresponding
chromosomes and exchange bits of genetic material. In women, X chromosomes pair;
in men, the X and Y chromosome pair. After the exchange, the chromosomes
separate, and meiosis continues.
In some cases, the Xs or the X chromosome and Y chromosome fail to pair and
fail to exchange genetic material. Occasionally, this results in their moving
independently to the same cell, producing either an egg with two Xs, or a sperm
having both an X and a Y chromosome. When a sperm having both an X and a Y
chromosome fertilizes an egg having a single X chromosome, or a normal Y-
bearing sperm fertilizes an egg having two X chromosomes, an XXY male is
Because they often don't appear any different from anyone else, many XXY males
probably never learn of their extra chromosome. However, if they are to be
diagnosed, chances are greatest at one of the following times in life: before or
shortly after birth, early childhood, adolescence, and in adulthood (as a result
of testing for infertility).
In recent years, many XXY males have been diagnosed before birth, through
amniocentesis or chorionic villus sampling (CVS). In amniocentesis, a sample of
the fluid surrounding the fetus is withdrawn. Fetal cells in the fluid are then
examined for chromosomal abnormalities. CVS is similar to amniocentesis, except
that the procedure is done in the first trimester, and the fetal cells needed
for examination are taken from the placenta. Neither procedure is used
routinely, except when there is a family history of genetic defects, the
pregnant woman is older than 35, or when other medical indications are present.
"If I were going to say something to parents who have had a prenatal
diagnosis, it would be 'You are so lucky that you know," said Melissa, the
mother of one XXY boy. "Because there are parents who don't know that their
sons have this problem. And they will never be able to help them lead a normal
life. But you can."
The next most likely opportunity for diagnosis is when the child begins
school. A physician may suspect a boy is an XXY male if he is delayed in
learning to talk and has difficulty with reading and writing. XXY boys may also
be tall and thin and somewhat passive and shy. Again, however, there are no
guarantees. Some of the boys who fit this description will have the XXY
chromosome count, but many others will not.
A few XXY males are diagnosed at adolescence, when excessive breast
development forces them to seek medical attention. Like some chromosomally
normal males, many XXY males undergo slight breast enlargement at puberty. Of
these, only about a third-10 percent of XXY males in all-will develop breasts
large enough to embarrass them.
The final chance for diagnosis is at adulthood, as a result of testing for
infertility. At this time, an examining physician may note the undersized testes
characteristic of an XXY male. In addition to infertility tests, the physician
may order tests to detect increased levels of hormones known as gonadotropins,
common in XXY males.
A karyotype is used to confirm the diagnosis. In this procedure, a small
blood sample is drawn. White blood cells are then separated from the sample,
mixed with tissue culture medium, incubated, and checked for chromosomal
abnormalities, such as an extra X chromosome.
What to tell families, friends and xxy boys
Expectant parents awaiting the arrival of their XXY baby have difficult choices
to make: whom to tell-and how much to tell about their son's extra chromosome.
Fortunately, however, there are some guidelines that new parents can take into
account when making their decisions.
One school of thought holds that the best course is to go on slowly, waiting
at least 1 year before telling anyone-grandparents included-about the child's
extra chromosome. Many people are frightened by the diagnosis, and their fears
will color their perceptions of the child. For example, some people may confuse
the term Klinefelter syndrome with Down syndrome, a condition resulting in mild
to moderate mental retardation.
Others may prefer to reveal the diagnosis early. Some parents have found that
grandparents, aunts, uncles-and even extended family members-are more supportive
when given accurate information. Another important decision parents must make is
when to tell their son about his diagnosis. Some experts recommend telling the
child early. When the truth is withheld, children often suspect that their
parents are hiding something and may imagine a condition that is worse than
their actual diagnosis.
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.
Soon after, he can be filled in on the details: that the cell difference is due
to an additional X chromosome, which is responsible for his undersized testes
and any reading difficulties he may have. At this time, the child can be
reassured that he does not have a disease and will not become sick. The child
should also be told that some people may misunderstand this information and that
he should exercise discretion in sharing it with others.
By roughly the age of 12, depending on the child's emotional maturity, he can
be told that he will most probably be infertile. Parents should stress that
neither the X chromosome nor the infertility associated with it mean that he is
in any way less masculine than other males his age. The child's parents or his
physician can explain that although he may not be able to make a baby, he can
consider adopting one. Parents may also need to reassure an XXY boy that his
small testes will in no way interfere with his ability to have a normal sex
Adherents of this school of thought believe that learning about possible
infertility in such a gradual manner will be less of a shock than finding out
about it all at once, late in the teen years.
Conversely, 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.
Moreover, children, when making friends, tend to share secrets. But childhood
friendships may be fleeting, and early confidences are sometimes betrayed. A
malicious or thoughtless child may tell all the neighborhood children that his
former companion is a "freak" because he has an extra chromosome.
For this reason, the best time to reveal the information may be mid-to-late
adolescence, when an XXY male is old enough to understand his condition and
better able to decide with whom he wishes to share this knowledge.
According to Dr. Robinson, the director of the NICHD-funded study, XXY babies
differ little from other children their age. They tend to start life as what
many parents call "good" babies-quiet, undemanding, and perhaps even a
little passive. As toddlers, they may be somewhat shy and reserved. They usually
learn to walk later than most other children, and may have similar delays in
learning to speak.
In some, the language delays may be more severe, with the child not fully
learning to talk until about age 5. Others may learn to speak at a normal rate,
and not meet with any problems until they begin school, where they may
experience reading difficulties. A few may not have any problems at all-in
learning to speak or in learning to read.
XXY males usually have difficulty with expressive language the ability to put
thoughts, ideas, and emotions into words. In contrast, their faculty for
receptive language-understanding what is said-is close to normal.
"It's one of the conflicts they have," said Melissa, the mother of
an XXY boy. "My son can understand the conversations of other 10 year olds.
But his inability to use the language the way other 10-year olds use it makes
him stand out."
In addition to academic help, XXY boys, like other language disabled
children, may need help with social skills. Language is essential not only for
learning the school curriculum, but also for building social relationships. By
talking and listening, children make friends-in the process, sharing
information, attitudes, and beliefs. Through language, they also learn how to
behave-not just in the schoolroom, but also on the playground. If their sons'
language disability seems to prevent them from fitting in socially, the parents
of XXY boys may want to ask school officials about a social skills training
Throughout childhood-perhaps, even, for the rest of their lives-XXY boys
retain the same temperament and disposition they first displayed as infants and
toddlers. As a group, they tend to be shy, somewhat passive, and unlikely to
take a leadership role. Although they do make friends with other children, they
tend to have only a few friends at a time. Researchers also describe them as
cooperative and eager to please.
Detecting language problems early
The parents of XXY babies can compensate for their children's language
disability by providing special help in language development, beginning at an
early age. However, there is no easy formula to meet the language needs of all
XXY boys. Like everyone else, XXY males are unique individuals. A few may not
have any trouble learning to read and write, while the rest may have language
impairments ranging from mild to severe.
If their son's speech seems to be lagging behind that of other children,
parents should ask their child's pediatrician for a referral to a speech
pathologist for further testing. A speech pathologist specializes in the
disorders of voice, speech, and language. (The American Speech, Language and
Hearing Association, listed in the reference section, distributes a free
pamphlet on the stages of language development during the first 5 years of
Parents should also pay particular attention to their children's hearing.
Like other small children, XXY infants and toddlers may suffer from frequent ear
infections. With any child, such infections may impair hearing and delay the
acquisition of language. Such a hearing impairment may be a further setback for
an XXY child who is already having language difficulties.
Guidelines for detecting language problems
Shortly after the first birthday, children should be able to make their wishes
known with simple one word utterances. For example, a child may say
"milk" to mean "I want more milk." Gradually, children begin
to combine words to produce two-word sentences, such as "More milk."
By age three, most children use an average of about four words per sentence.
If a child is not communicating effectively with single words by 18 to 24
months, then parents should seek a consultation with a speech and language
The xxy boy in the classroom
Although there are exceptions, XXY boys are usually well behaved in the
classroom. Most are shy, quiet, and eager to please the teacher. But when faced
with material they find difficult, they tend to withdraw into quiet daydreaming.
Teachers sometimes fail to realize they have a language problem, and dismiss
them as lazy, saying they could do the work if they would only try. Many become
so quiet that teachers forget they're even in the room. As a result, they fall
farther and farther behind, and eventually may be held back a grade.
Help under the law
According to Dr. Robinson, XXY boys do best in small, uncrowded classrooms where
teachers can give them a lot of individual attention. He suggests that parents
who can meet the expense consider sending their sons to a private school
offering special educational services.
Parents who cannot afford private schools should become familiar with Public
Law 94-142, the Education of the Handicapped Act-now called the Individuals with
Disabilities Education Act. This law, adopted by Congress in 1975, states that
all children with disabilities have a right to a free, appropriate public
education. The law cannot ensure that every child who needs special educational
services will automatically get them. But the law does allow parents to take
action when they suspect their child has a learning disability.
Chances for success are greatest for parents who are well informed and work
cooperatively with the schools to plan educational and related service programs
for their sons. For in-depth information on Public Law 94-142, parents may
contact the National Information Center for Children and Youth with Disabilities
(NICHCY), listed in the Resources section.
Parents may also wish to contact their local and state boards of education
for information on how the law has been implemented in their area. In addition,
local educational groups may be able to provide useful information on working
with school systems. Parents should also consider taking a course in educational
advocacy. The local public school system, the state board of education, or local
parents groups may be able to tell parents where they can enroll in such a
For information on learning disabilities, parents can contact the Learning
Disabilities Association of America and the Orton Dyslexia Society, both listed
in the reference section.
Services for infants, toddlers and pre-schoolers
The chances for reducing the impact of a learning disability are greatest in
early childhood. Public Law 99-457 is an amendment to Public Law 94-142 that
assists states in providing special educational services for infants, toddlers,
and preschoolers. Eligibility requirements and entrance procedures vary from
state to state. To learn the agencies to contact in their area, parents may call
the Federation for Children with Special Needs (listed in the Resources
section). The NICHCY (also listed in the Resources section) distributes the
brochure "A Parent's Guide to Accessing Programs for Infants, Toddlers, and
Preschoolers with Handicaps."
XXY males often have decreased immediate auditory recall they have trouble
remembering what they have just heard. Parents and teachers can help them
remember by approaching memory through visual channels. Illustrating words with
pictures may help. Gesturing is another useful technique. For example, a teacher
might accompany the word "yes" with a nod of the head. Similarly,
shaking the head from side to side is the universal gesture for "no."
Other useful gestures include waving goodbye, showing the child an upraised palm
to indicate "stop," and holding the arms outstretched to mean "so
XXY males frequently have trouble finding the right word to describe an
object or a situation. Parents and teachers can help them build vocabulary
through a variety of techniques. One way is to provide them with synonyms, such
as pointing out that a car is also called an automobile. Another important
teaching tool is categorizing-showing the child that an item belongs to a larger
class of items. With this technique, a child could be told that cars, buses,
trucks, and bicycles are all vehicles, machines that carry people and things
from place to place.
Because XXY boys have difficulty expressing themselves, they may do poorly on
essay-style test questions. Multiple choice questions will give teachers a
better idea of what an XXY child has learned-and prove less stressful for him as
well. Similarly, rather than asking an open-ended question, parents and teachers
may wish to present alternatives. Instead of asking "What would you 'like
to do now?" they may wish to offer a choice: "Would you rather work on
your spelling or work on your math?"
Parents and teachers can help XXY boys develop the ability to express
themselves through solicited dialogue engaging them in conversation through a
series of questions. The same technique can be used to get the child to develop
his narrative (storytelling) abilities. For example, a parent might begin by
asking a child what he did at recess that day, and by following up with
questions that get the child to talk about his activities: "Did you go down
the slide? Were you afraid when you climbed all the way to the top of the
ladder? And then what? Did you go on the seesaw? Who sat on the other end?"
Parents can also help XXY boys develop their expressive language abilities
simply by providing good examples. Through a technique known as modeling, they
can help organize their children's thoughts and provide them with examples of
how to express oneself. For instance, if a younger child indicated that he
wanted a toy fire engine by pointing at it and grunting, the parent could hand
it to him while saying "Here you are. This is a fire engine."
Similarly, if an older child asked "Are we going to put the stuff in the
thing?", the parent might reply "Yes, we're going to put the oranges
in the shopping cart."
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. First, teachers can reduce distraction by placing them in
front row seats. Teachers also should present information slowly and repeat key
points several times, if necessary. XXY boys should not be given tasks that have
many small steps. Rather, each step should be presented individually. On
completion, the child may then be asked to work on the next item in the series.
As mentioned above, XXY boys may withdraw from material they find difficult
and retreat into day dreaming. A teacher or parent should gently regain the
child's attention and help him to focus again on the task at hand. Similarly,
XXY boys may have difficulty putting one task aside and beginning another one.
Again, the parent or teacher should gently shift the child's attention, by
saying something like "Drawing time is over. Let's put away the crayons and
take out the math book."
-adapted from John Graham et al., "Oral and Written Language
Abilities of XXY Boys: Implications for Anticipatory Guidance, "
Pediatrics, Vol. 81 (6), June 1988.
In general, XXY boys enter puberty normally, without any delay of physical
maturity. But as puberty progresses, they fail to keep pace with other males. In
chromosomally normal teenaged boys, the testes gradually increase in size, from
an initial volume of about 2 ml, to about 15 ml. In XXY males, while the penis
is usually of normal size, the testes remain at 2 ml, and cannot produce
sufficient quantities of the male hormone testosterone. As a result, many XXY
adolescents, although taller than average, may not be as strong as other
teenaged boys, and may lack facial or body hair.
As they enter puberty, many boys will undergo slight breast enlargement. For
most teenaged males, this condition, known as gynecomastia, tends to disappear
in a short time. About one-third of XXY boys develop enlarged breasts in early
adolescence slightly more than do chromosomally normal boys. Furthermore, in XXY
boys, this condition may be permanent. However, only about 10 percent of XXY
males have breast enlargement great enough to require surgery.
Most XXY adolescents benefit from receiving an injection of testosterone
every 2 weeks, beginning at puberty. The hormone increases strength and brings
on a more muscular, masculine appearance. More information about testosterone
and XXY males can be found in the section titled "Testosterone
Adolescence and the high school years can be difficult for XXY boys and their
families, particularly in neighborhoods and schools where the emphasis is on
athletic ability and physical prowess.
"They're usually tall, good-looking kids, but they tend to be
awkward," Dr. Robinson said of the XXY teenagers he has met through his
study. "They don't necessarily make good football players or good
Lack of strength and agility, combined with a history of learning
disabilities, may damage self-esteem. Unsympathetic peers, too, sometimes may
make matters worse, through teasing or ridicule.
"Lots of kids have a tough time during adolescence," Dr. Robinson
said. "But a higher proportion of XXY boys have a tough time. High school
is very competitive, and these kids are not very good competitors, in
Dr. Robinson again stressed, however, that while XXY males share many
characteristics, they cannot be pigeonholed into rigid categories. Several of
his patients have played football, and one, in particular, is an excellent
Damage to self esteem may be more severe in XXY teenagers who are diagnosed
in early or late adolescence. Teachers-and even parents-may have dismissed their
scholastic difficulties as laziness. Lack of athletic prowess and the inability
to use language properly in social settings may have helped to isolate them from
their peers. Some may react by sliding quietly into depression and withdraw from
contact with other people. Others may find acceptance in a dangerous crowd.
For these reasons, XXY males diagnosed as teenagers may need psychological
counseling as well as help in overcoming their learning disabilities. Help with
learning disabilities is available through public school systems for XXY males
high-school age and under. Referrals to qualified mental health specialists may
be obtained from family physicians.
Ideally, XXY males should begin testosterone treatment as they enter puberty.
XXY males diagnosed in adulthood are also likely to benefit from the hormone. A
regular schedule of testosterone injections will increase strength and muscle
size, and promote the growth of facial and body hair.
In addition to these physical changes, testosterone injections often bring on
psychological changes as well. As they begin to develop a more masculine
appearance, the self-confidence of XXY males tends to increase. Many become more
energetic and stop having sudden, angry changes in moods. What is not clear is
whether these psychological changes are a direct result of testosterone
treatment or are a side benefit of the increased self confidence that the
treatment may bring. 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
Other benefits of testosterone treatment may include decreased need for
sleep, an enhanced ability to concentrate, and improved relations with others.
But to obtain these benefits an XXY male must decide, on his own, that he is
ready to stick to a regular schedule of injections.
Sometimes, younger adolescents, who may be somewhat immature, seem not quite
ready to take the shots. It is an inconvenience, and many don't like needles.
Most physicians do not push the young-men to take the injections. Instead,
they usually recommend informing XXY adolescents and their parents about the
benefits of testosterone injections and letting them take as much time as they
need to make their decision.
Individuals may respond to testosterone treatment in different ways. Although
the majority of XXY males ultimately will benefit from testosterone, a few will
To ensure that the injections will provide the maximum benefit, XXY males who
are ready to begin testosterone injections should consult a qualified
endocrinologist (a specialist in hormonal interactions) who has experience
treating XXY males.
Side effects of the injections are few. Some individuals may develop a minor
allergic reaction at the injection site, resulting in an itchy welt resembling a
mosquito bite. Applying a non-prescription hydrocortisone cream to the area will
reduce swelling and itching.
In addition, testosterone injections may result in a condition known as
benign prostatic hyperplasia (BPH). This condition is common in chromosomally
normal males as well, affecting more than 50 percent of men in their sixties,
and as many as 90 percent in their seventies and eighties. In XXY males
receiving testosterone injections, this condition may begin sometime after age 40.
The prostate is a small gland about the size of a walnut, which helps to
manufacture semen. The gland is located just beneath the bladder and surrounds
the urethra, the tube through which urine passes out of the body.
In BPH, the prostate increases in size, sometimes squeezing the bladder and
urethra and causing difficulty urinating, "dribbling" after urination,
and the need to urinate frequently.
XXY males receiving testosterone injections should consult their physicians
about a regular schedule of prostate examinations. BPH can often be detected
early by a rectal exam. If the prostate greatly interferes with the flow of
urine, excess prostate tissue can be trimmed away by a surgical instrument that
is inserted in the penis, through the urethra.
Occasionally, variations of the XXY chromosome count may occur, the most common
being the XY/XXY mosaic. In this variation, some of the cells in the male's body
have an additional X chromosome, and the rest have the normal XY chromosome
count. The percentage of cells containing the extra chromosome varies from case
to case. In some instances, XY/XXY mosaics may have enough normally functioning
cells in the testes to allow them to father children.
A few instances of males having two or even three additional X chromosomes
have also been reported in the medical literature. In these individuals, the
classic features of Klinefelter syndrome may be exaggerated, with low I.Q. or
moderate to severe mental retardation also occurring.
In rare instances, an individual may possess both an additional X and an
additional Y chromosome. The medical literature describes XXYY males as having
slight to moderate mental retardation. They may sometimes be aggressive or even
violent. Although they may have a rounded body type and decreased sex drive,
experts disagree whether testosterone injections are appropriate for all of
One group of researchers reported that after receiving testosterone
injections, an XXYY male stopped having violent sexual fantasies and ceased his
assaults on teenaged girls. In contrast, Dr. Robinson found that testosterone
injections seemed to make an XXYY boy he had been treating more aggressive.
Scientists admit, however, that because these cases are so rare, not much is
known about them. Most of the XXYY males who have been studied were referred to
treatment because they were violent and got into trouble with the law. It is not
known whether XXYY males are inherently aggressive by nature, or whether only a
few extreme individuals come to the attention of researchers precisely because
they are aggressive.
The parents of XXY boys are sometimes concerned that their sons may grow up to
be homosexual. This concern is unfounded, however, as there is no evidence that
XXY males are any more inclined toward homosexuality than are other men.
In fact, the only significant sexual difference between XXY men and teenagers
and other males their age is that the XXY males may have less interest in sex.
However, regular injections of the male sex hormone testosterone can bring sex
drive up to normal levels.
In some cases, testosterone injections lead to a false sense of security:
After receiving the hormone for a time, XXY males may conclude they've derived
as much benefit from it as possible and discontinue the injections. But when
they do, their interest in sex almost invariably diminishes until they resume
The vast majority of XXY males do not produce enough sperm to allow them to
become fathers. If these men and their wives wish to become parents, they should
seek counseling from their family physician regarding adoption and infertility.
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
In addition, a few individuals who believe themselves to be XXY males may
actually be XY/XXY mosaics. Along with having cells with the XXY chromosome
count, these males may also have cells with the normal XY chromosome count. If
the number of XY cells in the testes is great enough, the individual should be
able to father children.
Karyotyping, the method traditionally used to identify an individual's
chromosome count, may sometimes fail to identify XY/ XXY mosaics. For this
reason, a karyotype should never be used to predict whether an individual will
be infertile or not.
Compared with other males, XXY males have a slightly increased risk of
autoimmune disorders. In this group of diseases, the immune system, for unknown
reasons, attacks the body's organs or tissues. The most well known of these
diseases are type I (insulin dependent) diabetes, autoimmune thyroiditis, and
lupus erythematosus. Most of these conditions can be treated with medication.
XXY males with enlarged breasts have the same risk of breast cancer as do
women-roughly 50 times the risk XY males have. For this reason, these XXY
adolescents and men need to practice regular breast self examination. The free
booklet Breast Exams: What You Should Know is available from the National Cancer
Institute, listed in the Resources section. The last page of the booklet is a
pullout chart listing the instructions for breast self examination. Although the
booklet was written primarily for women, the breast self examination technique
also can be used by XXY males. XXY males may also wish to consult their
physicians about the need for more thorough breast examinations by medical
In addition, XXY males who do not receive testosterone injections may have an
increased risk of developing osteoporosis in later life. In this condition,
which usually afflicts women after the age of menopause, the bones lose calcium,
becoming brittle and more likely to break.
Unfortunately, comparatively little is known about XXY adults. Studies in the
United States have focused largely on XXY males identified in infancy from large
random samples. Only a few of these individuals have reached adulthood; most are
still in adolescence. At this time, researchers simply do not know what kind of
adults they will become.
"Some of them have really struggled through adolescence," said Dr.
Bruce Bender, the psychologist for the NICHD-sponsored study of XXY males.
"But we don't know whether they'll have serious problems in adulthood, or,
like many troubled teenagers, overcome their problems and lead productive
Comparatively few studies of XXY males diagnosed in adulthood have been
conducted. By and large, the men who took part in these studies were not
selected at random but identified by a particular characteristic, such as
height. For this reason, it is not known whether these individuals are truly
representative of XXY men as a whole or represent a particular extreme.
One study found a group of XXY males diagnosed between the ages of 27 and 37
to have suffered a number of setbacks, in comparison to a similar group of XY
males. The XXY men were more likely to have had histories of scholastic failure,
depression and other psychological problems, and to lack energy and enthusiasm.
But by the time the XXY men had reached their forties, most had surmounted
their problems. The majority said that their energy and activity levels had
increased, that they were more productive on the job, and that their
relationships with other people had improved. In fact, the only difference
between the XY males and the XXY males was that the latter were less likely to
have been married.
That these men eventually overcame their troubled pasts is encouraging for
all XXY males and particularly encouraging for those diagnosed in childhood. Had
they received counseling, support, and testosterone treatments beginning in
childhood, these men might have avoided the difficulties of their twenties and
Although a supportive environment through childhood and adolescence appears
to offer the greatest chance for a well-adjusted adulthood, it is not too late
for XXY men diagnosed as adults to seek help.
Research has shown that testosterone injections, begun in adulthood, can be
beneficial. Psychological counseling also offers the best hope of overcoming
depression and other psychological problems. For referrals to endocrinologists
qualified to administer testosterone or to mental health specialists, XXY men
should consult their physicians.
The Orton Dyslexia Society and the Learning Disabilities Association of
America, listed in the Resources section, can provide information on overcoming
a reading disability.
Office of Research Reporting, NICHD
The American Speech Language and Hearing Association
10801 Rockville Pike
Rockville, MD 20852
Distributes a pamphlet parents may consult to determine if their children's
communication abilities are developing at a normal rate.
The Federation for Children with Special Need
95 Berkely Street, Suite 104
Boston, MA 02116
Maintains a listing of local and state agencies providing special educational
services for infants, toddlers, and preschoolers under Public Law 99-457
Learning Disabilities Association of America
4156 Library Road
Pittsburgh, PA 15234
Provides information on dyslexia and other learning disabilities. Has local
chapters throughout the country.
K' S. and Associated
P.O. Box 119
Roseville, CA 95678
Support group for XXY males as well as males with other sex chromo-some
disorders. Operated by "Melissa," mother of a 12-year-old XXY boy
Provides literature on XXY males and other chromosome disorders, periodic newsletter.
The National Cancer Institute
Building 31, Room 1OA16
9000 Rockville Pike
Bethesda, MD 20982
Offers the free booklet Breast Exams: What You Should Know. The last
page of the booklet is a pull-out chart listing the instructions for breast self
examination. Although the booklet was written primarily for women, the breast
self examination technique also can be used by XXY males.
The National Information Center for Children and Youth With Disabilities (NICHCY)
P.O. Box 1492
Washington, DC 20013
(202) 884.8200 (Voice/TTD)
Distributes information on Public Law 94-142, the Individuals with Disabilities Education Act.
The Orton Dyslexia Society
Chester Building, Suite 382
8600 La Salle Road
Baltimore, MD 21286
Provides information on dyslexia. Has local chapters throughout the country
Source: National Institutes of Health; NICHD