Turner syndrome
A girl with Turner syndrome only has one normal X sex chromosome, rather than the usual two (XX).
Everyone is born with 23 pairs of chromosomes. One pair of chromosomes the sex chromosomes determines the baby's gender.
One sex chromosome comes from the father and the other comes from the mother. The mother's contribution is always an X chromosome. The father's contribution can either be an X or a Y chromosome.
A baby girl usually has two X chromosomes (XX), and boys have an X and a Y chromosome (XY). The Y chromosome determines "maleness", so if it is missingas in Turner syndromethe sex of the child will invariably be female.
A female with Turner syndrome is missing part or all of one sex chromosome. This means she has just one complete X chromosome.
Thischromosome variation happens randomly when the baby is conceived in the womb. It is not linked to the mother's age.
The syndrome can either be described as:
Turner syndrome is a genetic disorder that only affects females. It causes a wide range of symptoms and some distinctive characteristics.
The symptoms of Turner syndrome vary depending on the age of the girl or woman affected.
Turner syndrome is a genetic condition caused by a missing or incomplete sex chromosome.
Turner syndrome is sometimes diagnosed before a baby is born, although it is often identified during childhood or at puberty.
There is no cure for Turner syndrome, but many of the associated symptoms, such as short stature, sexual development problems and learning difficulties, can be treated.