Variations in the number of copies of the X chromosome do occur in Klinefelter syndrome, and sometimes all the cells do not have an extra X chromosome. The most common mosaic pattern in Klinefelter syndrome is 46,XY/47, XXY and this indicates that some cells in the male body have the normal XY chromosome count while other cells have an additional X chromosome. Because of this mosaic pattern, there may be enough normally functioning cells to be able to have children. Often, men with less XXY cells and more cells with only XY will have less severe symptoms. Mosaicism is very complicated, and it is challenging to predict how a man will be affected. Medical geneticists and genetic counselors can help interpret confusing results in these situations.
Other Questions About Klinefelter syndrome
- Will my child be less severely affected if they have mosaic Klinefelter syndrome?
- Where do I find other families with a child with Klinefelter syndrome?
- Where can I find helpful resources for my patients with Klinefelter syndrome?
- What treatments are available for the hormone imbalances in Klinefelter syndrome?
- What specialists do people with Klinefelter syndrome need to see?
