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Finding out that your child has a genetic condition can be extremely challenging for parents. It may leave you wondering whether you will have to reassess everything you had planned and hoped for regarding your child’s and family’s future. But life does not stop with the discovery of an extra X or Y chromosome, nor will your child stop growing. Life will be different, but not without many of the same joys and challenges that all parents feel in their children’s lives.

Here you will find many resources to help you better understand your child and get the support you need to help guide them to maturity and their fullest potential.

Frequently Asked Questions

The questions below serve as a general preview for the more extensive list of Frequently Asked Questions on X and Y chromosome variations, grouped by condition, that is available here.

47,XXY, also commonly referred to as Klinefelter syndrome, is estimated to occur in 1 out of 600 males, making it the most common chromosomal disorder.  Rather than the usual pattern of 46 chromosomes, with one X chromosome and one Y chromosome, there is an additional X chromosome, resulting in a genetic signature of 47,XXY.  This happens when paired chromosomes fail to separate at the first or second stage of meiosis.  The exact cause is unknown.  The extra chromosome can come from either parent; there is little relation to either maternal or paternal age.  An extra chromosome in a pair (ie the X and Y chromosomes) is called a trisomy.  47,XXY, unlike most trisomy conditions, is highly survivable for the fetus and causes symptoms that vary greatly from one person to another.    An extra or missing sex chromosome yields a syndrome called sex chromosome aneuploidy.  A syndrome is a collection of symptoms and physical signs.  In some individuals, the manifestations of 47,XXY are mild and barely noticeable while in others, there is more severe symptomatology.

Rather than having the usual male pattern of 46 chromosomes with one X chromosome from the mother’s egg and one Y chromosome from the father’s sperm, individuals with 47,XYY are born with an additional Y chromosome. This results in the genetic signature of 47,XYY, which occurs in approximately 1 in every 1,000 males.

47,XYY results from an error in cell division when an egg or sperm is formed in a parent, or after fertilization, when the cells divide in the embryo. That means it, like other X and Y conditions, is not inherited, though the exact cause of the cell division errors is unknown.

An extra chromosome in a pair (i.e. the X and Y chromosomes) is called a trisomy. 47,XYY and the other trisomy sex chromosome conditions (47,XXY and Trisomy X), are highly survivable for the fetus, rarely cause severe disability, and can have symptoms that vary greatly from one person to another. In some males, the manifestations of 47,XYY are mild and barely noticeable while in others there are much more severe symptoms.

Trisomy X, also known as 47,XXX, is estimated to occur in 1 out of 1000 females. Rather than the usual female pattern of 46 chromosomes with two X chromosomes, there is an additional X chromosome, resulting in a genetic signature of 47,XXX. This happens when paired chromosomes fail to separate during meiosis, creating either an egg or a sperm with an extra X chromosome, or after fertilization during mitosis, when the cells divide in the embryo. The exact cause is unknown. The extra chromosome can come from either the egg or the sperm although in Trisomy X, it is more likely to be contributed by the egg. An extra chromosome in a pair (i.e. the X and Y chromosomes) is called a trisomy. There is some relationship to advanced maternal age, although it is not nearly as strong as in Down syndrome, which is also a trisomy condition involving chromosome 21. Unlike most trisomy conditions, Trisomy X and the other trisomy sex chromosome aneuploid conditions (47,XXY and 47,XYY) are highly survivable for the fetus and cause symptoms that vary greatly from one person to another. An extra or missing sex chromosome yields a syndrome called sex chromosome aneuploidy. A syndrome is a collection of symptoms and physical signs. In some females, the manifestations of 47,XXX, are mild and barely noticeable while in others, there are much more severe symptoms.

Before disclosing a diagnosis to relatives, such as grandparents, determine whether they are likely to be supportive and tolerant of a range of learning disabilities and other possible health and behavior problems. It is reasonable to wait with a prenatal diagnosis until your child demonstrates some developmental delay, and an explanation to grandparents or to siblings becomes necessary.

A significant factor in disclosure is the need for social benefits and supports. Most accommodations of any type have their basis in the American’ with Disabilities Act (ADA). The XXY individual may not be disabled and yet still qualify for services and accommodations. For example, a person with XXY may benefit from the protections and supports afforded by an IEP or 504 plan in school. In the case of a child with language, physical, learning or behavioral difficulties, disclosing the chromosomal condition to relatives is often reasonable and reassuring to them. It is important to know as much information as possible so that you can address concerns, particularly where the relative has heard one of the myths about 47,XXY.  Some of these myths suggest that 47,XXY causes intellectual and developmental disabilities (previously called mental retardation), increased criminal behavior, or that individuals with 47,XXY are actually women.

It is important to emphasize that most XXYs have IQs between 85 and 120, although some individuals with more than two additional chromosomes may have intellectual and developmental disabilities. In addition, XXYs as a group actually have lower than expected rates of criminal convictions, when compared with the general population of males. And, while respecting those XXYs who identify as a different gender, the presence of a Y chromosome almost always determines that a human develops as a male, although there are some syndromes (not related to 47,XXY) in which a human with a Y chromosome may develop as a female, rather than as a male.  A minority of XXYs identify as another gender or intersex.

Disclosure to an employer is rarely necessary unless the employee is seeking employment through a supported work program or is seeking some other special accommodations under the ADA. Genetic information should remain private because disclosing such information may make obtaining health or life insurance difficult. Employers or others may make unjustified assumptions that certain myths (cited above) are true for persons with 47,XXY. In some cases, however, disclosure may be necessary in order to obtain federally-mandated Family and Medical Leave, or some other benefit such as disability coverage or an accommodation under the ADA.

Disclosure to schools is necessary only if your child demonstrates significant learning or behavior problems that require special education classification, such as an IEP or Section 504 accommodation.  Schools will often be unaware of the condition, and staff will need to be educated about XXY, usually by the parent. Taking a selection of website printouts explaining the condition and its impact on learning can be very helpful.  Some parents have found that special education services are more likely to be appropriate when the pediatrician provides a diagnosis under the classification of “other health impaired” such as Pervasive Developmental Disorder-NOS (PDD), rather than 47,XXY. Schools understand autistic-like behavioral and language difficulties when they occur in high-functioning children, and many schools have programs in place to address these problems. In addition, these programs are mandated in many states for children with autism spectrum disorders, of which PDD is one. The schools may not realize that XXY children often have the same deficits and are also eligible for these services.

To access these accommodations, parents are well advised to learn the glossary of key terminology that helps make the case to qualify their child student for these supports. It also may be helpful to recruit local disabilities advocates, such as the ARC, to assist with the qualification process.

Individuals with 47,XXY fall in love just as other human beings do, so they should divulge their condition at the appropriate time in a developing relationship. If and as any given relationship advances past the casual dating phase, disclosure—along with thorough education about the condition—may well become advisable. Support groups and list-serves can be very helpful in introducing new couples to others who have been through building a relationship and a family.

Alan’s Story

“My son was diagnosed at 18 months. He is now 8. We take him to a speech therapist once a fortnight and he has a tutor for school. Although he has a modified IEP (individual education plan), he is doing O.K. at school. His strengths seem to be with people. He makes friends easily and quickly. He really knows how to have fun and is known for having a good time.”
Alan

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Latest News and Research

Exploring Klinefelter Syndrome

"The Impact of Living with Klinefelter Syndrome: A Qualitative Exploration of Adolescents and Adults" — This research article examines the medical, psychological, and social challenges that arise in individuals with 47,XXY as well as providing practical [...]

Expanding the Triple X Phenotype

"Expanding the Phenotype of Triple X Syndrome: A Comparison of Prenatal Versus Postnatal Diagnosis" —This cross-sectional study was published in the American Journal of Medical Genetics. It describes the diagnosis, physical aspects, medical problems, and neurodevelopmental [...]

A Klinefelter Update for Pediatricians

"Advances in the Interdisciplinary Care of Children with Klinefelter Syndrome"—This nearly 30-page story in the journal Advances in Pediatrics is directed at pediatricians and family physicians who treat children, and who may thus come across [...]

The Challenges of Klinefelter’s

"The Klinefelter Syndrome: Current Management and Research Challenges"—From the scientific journal, Andrology, this article summarizes the concluding “Round Table Discussion” of the 2nd International Workshop on the Klinefelter Syndrome in Munster, Germany, March, 2016. Topics [...]

For a library of past news items, click here.