47 XYY Syndrome

Below you will find more information about 47 XYY Syndrome from Medigest. If you believe that you are suffering from any of the symptoms of 47 XYY Syndrome it is important that you obtain an accurate diagnosis from a medical professional to ensure that you obtain the correct medication or treatment for your condition. There are medical conditions that carry similar symptoms associated with 47 XYY Syndrome and therefore the information provided by Medigest is offered as a guideline only and should never be used in preference to seeking professional medical advice. The information relating to 47 XYY Syndrome comes from a third party source and Medigest will not be held liable for any inaccuracies relating to the information shown.


The XYY syndrome should never be interchanged with the XXY syndrome which is popularly known as the Klinefelter's syndrome. XYY syndrome is a condition when a male patient acquires an extra Y chromosome in addition to the normal one X and one Y chromosomes. It is often argued whether the term 'syndrome' should be used in connection to the XYY condition since the patients' phenotypes are normal and they do not have knowledge of their karyotype.


About 1 in every 1,000 boys acquires the extra Y chromosome.


This condition cannot be corrected but to prevent the occurrence of this syndrome on the patient's posterity, it is best that genetic testing must be done.


47 XYY syndrome is not an inherited condition. This is just the result of an accidental event during sperm cell formation. The 'accident' happens either during metaphase I or metaphase II.

Characteristics and Features

Most of the males who acquire an additional Y chromosome do not show any physical abnormalities. It is often, too, that they do not encounter any medical problems in relation to their condition. It is only noted, though, that XYY males grow rapidly during their early childhood with about 7 centimeters above the normal boys' height. Some believe that severe cases of acne could also result with XYY syndrome but most dermatologists now doubt the connection of the two. Testosterone levels of XYY males remain normal and this is true whether the test is prenatal or postnatal. It is also good to note that these males grow like normal boys of their age and also do not come across the problem of infertility. Since no physical abnormalities show, this condition is only discovered during genetic testing. Although these XYY males do not show signs of their condition physically, it is highly noticeable that most of them suffer from delayed progress on their learning skills. About 50% have difficulties in learning language and speech. Records also show that XYY boys have lower IQ. Problems on behavior could also occur.

First Recorded Case

The very first known case of XYY syndrome was studied by a man named Avery Sandberg in the year 1961. This man, together with his colleagues, observed a subject who was 44 years old and had an average IQ and height. The condition manifested only when he learned that he had a daughter who suffered from Down syndrome.

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