Klinefelter Syndrome

Healthcare providers may diagnose Klinefelter syndrome during:

• Fetal development. Providers don’t often test fetuses for Klinefelter syndrome. If they detect the condition, it usually happens when running genetic tests (like chorionic villus sampling or amniocentesis) for other reasons.
• Childhood or adolescence. A provider may recommend testing if they notice atypical growth or development (related to puberty) during these years.
• Adulthood. Your provider may test for Klinefelter if you have low testosterone or fertility issues (trouble getting pregnant with your partner).

People with mild cases of Klinefelter syndrome — those without symptoms — may never even know they have the condition. For others, their providers only discover it during infertility testing.

The goal of testing is to detect and identify an extra X chromosome. The most common way to do this is with a karyotype test, which is a blood test that tells your provider the number and types of chromosomes present. Providers can use karyotyping on children, adults and even in fetuses before birth.

Healthcare providers recommend neuropsychological testing for children with Klinefelter syndrome. It’s best to test them at the time of diagnosis and again every few years. This can help identify any learning challenges and guide educators on how to help your child succeed.