What is KS/XXY?

This section explains what Klinefelter's Syndrome is and how it happens.

Klinefelter’s Syndrome is medical condition caused by you having an extra chromosome.

No-one can see your extra chromosomes and it is up to you who you want to tell.

KS/XXY is something you are born with –  like having green eyes. It isn’t an illness and it can’t be ‘fixed’, but you can get help if it is causing you problems.

Chromosomes are strands of DNA which make up the cells in your body. Boys usually have an X chromosome and a Y chromosome. Girls usually have two X chromosomes.

 Instead of having an X chromosome and a Y chromosome, you have two X chromosomes and a Y chromosome.

Some people prefer to call it Klinefelter’s Syndrome, some call it KS and others prefer XXY. The KSA calls it KS/XXY. They all mean the same thing.

For every 600 boys in your school, one will probably be XXY. It is as common as having red hair!