Normally each cell has twenty-three pairs of chromosomes. One of these pairs, the sex chromosomes, determines whether a baby will be a boy or a girl.

In a girl there will be two X's (46XX), however in Turner Syndrome one of the X chromosomes will be missing or altered slightly.

When an X chromosome is missing or different in all cells, this is described as 'Classical Turner Syndrome'. If the second X chromosome is missing or different only in some cells of the body, this is called 'Turner mosaicism'.  Having only one X chromosome does not make a Turner Syndrome girl any less feminine than a girl who does not have Turner Syndrome.

Nobody knows the reason why some girls will be born with Turner Syndrome and there does not appear to be anything parents can do to avoid one of their daughters having the condition.  It happens purely by chance.

Turner Syndrome can be diagnosed at any age from birth to adulthood.  To diagnose the condition the doctors have first to suspect it – usually they are alerted by some physical features. Some girls are diagnosed shortly after birth because they have puffy hands and feet or a heart problem, but if these features are not there the diagnosis may not be suspected. Many girls are diagnosed during childhood because they are smaller than their friends or compared to their brothers and sisters, or because they are growing slowly. If no one suspects they have Turner Syndrome it may be missed until puberty is delayed as that can be another clue. Some young adults are not diagnosed until they seek help because they have not started their periods.

For further information talk to your doctor.

Last updated: May 2009
CAID/SUEC/HGH016