Turner syndrome is a disorder caused by a partially or completely missing X chromosome. It is a condition that only affects females.
Most people have 46 chromosomes in each cell – 23 from their mother and 23 from their father. The 23rd pair of chromosomes is called the sex chromosomes – X and Y – because they determine whether a person is male or female. Most females have XX in most of their cells and most males have XY in most of their cells.
Females with Turner syndrome are missing all or part of one of their X chromosomes.
For more information on chromosomes, see Cells 101.