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Unlike many conditions that have obvious, defined symptoms well-known to physicians and the general population, X and Y chromosome variations often affect people only subtly, with mild and mysterious symptoms that are often dismissed as normal developmental variations or individual quirks. This can delay diagnosis for years, much to the frustration of those who experience them.

Being diagnosed with a genetic condition as an adult can be a highly distressing experience. But for many people, it can also come as a profound relief. Finally, they have an answer to the questions that have simmered in their lives about feeling different, with challenges that did not seem to affect other family members or their peers.

At AXYS, we also know that a diagnosis can act as a springboard to new knowledge, new perspective, and a new resolve for you to finally obtain the support you need to make the most of your life. Whether you were diagnosed just recently or years ago and are still sorting out the implications, you can always expand your knowledge base and arm yourself with new tools and approaches to addressing your condition. Over the years, we have seen countless people find their way forward and accomplish more than they thought was possible before their diagnosis.

Toward that end, the entire AXYS community stands ready to assist you in all the ways described in this website. Whether you gain knowledge from what you read here, the conversations taking place at clinics and conferences or daily on our Facebook page, or via  support from our Helpline (1‑267‑338‑4262), you can rest assured that others are available and supportive of your desire to lead a productive and rewarding life.

Frequently Asked Questions

The different conditions occur at varying rates in the population. 47,XXY occurs in approximately 1 in 600 males, 47,XYY in 1 in 1,000 males. 47,XXX (Trisomy X) occurs in approximately 1 in 1,000 females. 48,XXYY is comparatively rare at approximately 1 in 18,000-40,000 males.

Although most people born with  X and Y variations exhibit some degree of cognitive impairment, severity can vary quite widely among the different conditions and even among different people with the same condition. Speech delay, low muscle tone and poor coordination, learning disabilities, and tall stature are other common symptoms, as are psychological challenges of anxiety, depression, attention deficits and social immaturity. Only rarely do individuals exhibit a great number of these symptoms, and indeed, the fact that many exhibit only a few, with limited severity, is why so many people with an X or Y variation remain undiagnosed for much of their lives.

Approximately 75% go undiagnosed their entire lives. This reflects the fact that the presenting symptoms of the conditions are often easily passed off as part of normal human variation, despite the considerable educational and social challenges they may present to affected individuals and their families.

No. The extra chromosomes in these conditions result from an error in cell division when an egg or sperm is formed, or after fertilization. Males have one X chromosome and females have two, so both the mother and father can contribute an extra X. Since females lack any Y chromosomes, only males can contribute an extra Y to their child. In 48,XXYY, the error in cell division occurs when the sperm is formed.  The father contributes the extra X and Y chromosomes, in all cases.

Susan’s Story

“I always struggled in school, especially in reading. But a lot of kids were in the same boat so I didn’t stand out too much. I made it through high school and even some college before I got a job. But social life was never easy for me and I carried a lot of self-esteem issues into adulthood. Finally, my doctor suggested the possibility of testing to rule out any organic causes, and I was amazed to find out I have Trisomy X. It was more a feeling of relief than anything else. A lot of puzzle pieces fell into place that day.”



Professionals who specialize in XXY, XYY, Trisomy X, and XXYY

Research and clinical trials for those with XXY, XYY, Trisomy X, and XXYY.

Clinics for individuals with XXY, XYY, Trisomy X, and XXYY

Support groups for individuals with XXY, XYY, Trisomy X, and XXYY

Latest News & Research

Exploring the Strengths of Students with X&Y Variations

"Children with sex chromosome aneuploidies (SCAs) are often characterized in the literature by limitations and pathologies related to the genetic diagnosis. This study aimed to broaden the SCA phenotype by describing parent reported character and [...]

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 [...]

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The Triple X Syndrome 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 [...]

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 [...]