Klinefelter syndrome is also known as XXY syndrome.


How can you diagnose Klinefelter syndrome in babies and toddlers?

A geneticist can diagnose Klinefelter syndrome before your son is born through a fetal cytogenetic analysis.

Your pediatrician may suspect Klinefelter syndrome if your infant son has:

However, 75% of boys with Klinefelter syndrome develop normal height and weight until they reach age 4 or 5. In 25% of boys, there is a telltale condition called clinodactyly, where the little finger curves toward the ring finger because the middle bone is wedge-shaped instead of rectangular.


How can you diagnose Klinefelter syndrome in school age boys?

Your pediatrician may investigate your school-age son for Klinefelter syndrome if he has this characteristic appearance:

Klinefelter boy

You may ask your pediatrician to investigate your son for Klinefelter syndrome if he has:


How can you diagnose Klinefelter syndrome during puberty?

klinefelter teenager

Your doctor may suspect Klinefelter syndrome when your boy reaches puberty if he has:

If your doctor suspects your son has the androgen deficiency that accompanies Klinefelter syndrome, he will likely be sent to a lab for these blood tests:

You may ask your doctor to perform genetic screening for Klinefelter syndrome if your son exhibits:


How can you diagnose Klinefelter syndrome in adult men?

klinefelter adultklinefelter man

Most men with Klinefelter syndrome do not exhibit symptoms. You may first notice a problem when you experience:


When should I tell my son he has Klinefelter syndrome?

Experts recommend explaining to your affected child that he has Klinefelter syndrome when he reaches his mid-to-late teens. He should be old enough by then to understand its implications. You can download a FREE booklet about Klinefelters which will help him to deal with his symptoms.


Understand more on Klinefelter:

What is Klinefelter Syndrome?

Klinefelter facts & treatment options

Why we need testosterone

The information in this article has been taken with permission from the official Lawley booklet on Understanding Kinefelter Syndrome.