Pediatric Klinefelter Syndrome

Klinefelter syndrome is a genetic condition in which boys are born with an extra sex chromosome in their cells.

What is Pediatric Klinefelter Syndrome?

Klinefelter syndrome (also known as XXY syndrome) is a genetic syndrome that is found only in males. Boys with Klinefelter Syndrome are born with an extra sex chromosome in their cells.

Typically, females have two X chromosomes, while males have one X and one Y chromosome. In males with Klinefelter syndrome, there are two X chromosomes and one Y chromosome (XXY). Rarely there are additional X chromosomes that are present in the cells (XXXY).

As the boys develop into adolescents (12-17 years of age*), their condition becomes more apparent, as they can be taller than other boys their age, with disproportionally long arms and legs.

What are the causes of Pediatric Klinefelter Syndrome?

While Klinefelter Syndrome is congenital (present at birth), is not hereditary (passed down in families). It occurs during fetal development when the chromosomes divide.

Pediatric Klinefelter Syndrome Doctors and Providers