Helpline 0300 111 4748

KS/XXY for Adults

Klinefelter’s Syndrome (KS)/XXY is a common congenital condition (that means it is present at birth).

It is found in around 1 in 600 live male births and is caused by the presence of one or more additional sex chromosomes.


Chromosomes are genetic material. Males typically have one X and one Y chromosome (XY) and females have two X chromosomes (XX). People with KS have two X chromosomes and one Y chromosome (XXY). This is why the KSA refers to the condition as KS/XXY.

KS/XXY is diagnosed by a genetic blood test which identifies the karyotype i.e. the number, size and shape of the chromosomes.

Although the condition is relatively common, its effects are not well understood.

Scientific background

Common symptoms



Common health issues

Fertility options

The future

Useful links

If you would like to talk to someone please call our Helpline:

0300 111 47 48.

Please remember that as the KSA is run entirely by volunteers. Sometimes there may not be anyone available to take your call. Please leave a message with your email address or phone number and we will get back to you.


If you are feeling suicidal,  please contact the Samaritans
They are available 24 hours per day, phone: 116 123 or visit