Klinefelter syndrome

What is Klinefelter syndrome?

This rare disease is a genetic syndrome which occurs when a male infant is born with an extra X chromosome, instead of being born with XY chromosomes. Another name for Klinefelter syndrome is XXY syndrome.

There are three types of the syndrome: where the male has an extra X chromosome in each cell, the mosaic form of the syndrome which is an extra X chromosome in only some of the cells, or the presence of more than one extra X chromosome which is particularly rare and a very severe form of the condition.

What gene changes cause Klinefelter syndrome?

The syndrome is caused by the presence of an extra X chromosome in the either all or some of the cells of males. Usually there is no known reason for the presence of this extra chromosome, other than it happens during reproduction. There may be some evidence to suggest a higher risk of it occurring, the older the mother is at the time of reproduction.

The syndrome is not inherited as males with the syndrome are infertile.

What are the main symptoms of Klinefelter syndrome?

The symptoms of the syndrome can vary widely between individuals. A lot of males with the syndrome are not diagnosed until puberty or even adulthood due to the absence of symptoms, or the presence of only very mild ones.

The symptoms of the syndrome may vary with age. But the main symptoms include hypotonia (low muscle tone in infancy), delayed physical development and delayed speech development. In later childhood learning difficulties are often identified.

Most males with the syndromes experience issues concerning their puberty. Either they don’t experience it, it starts much later than the average or it never ends.

Physical symptoms of the syndrome include longer arms and legs, a tall stature but a shorter torso.

How does someone get tested for Klinefelter syndrome?

The initial testing for Klinefelter syndrome can begin with facial analysis screening, through the FDNA Telehealth telegenetics platform, which can identify the key markers of the syndrome and outline the need for further testing. A consultation with a genetic counselor and then a geneticist will follow.

Based on this clinical consultation with a geneticist, the different options for genetic testing will be shared and consent will be sought for further testing.

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