Definition:
Turner syndrome is a genetic condition in which a female does not have the usual pair of two X chromosomes.
Alternative Names:
Bonnevie-Ullrich syndrome; Gonadal dysgenesis; Monosomy X
Causes, incidence, and risk factors:
Humans have 46 chromosomes. Chromosomes contain all of your genes and DNA, the building blocks of the body. Two of these chromosomes, the sex chromosomes, determine if you become a boy or a girl. Females normally have two of the same sex chromosomes, written as XX. Males have an X and a Y chromosome (written as XY). In Turner syndrome, cells are missing all or part of an X chromosome. The condition only occurs in females. Most commonly, the female patient has only one X chromosome. Others may have two X chromosomes, but one of them is incomplete. Sometimes, a female has some cells with two X chromosomes, but other cells have only one. Turner syndrome occurs in about 1 out of 2,000 live births.
References:
T Morgan. Turner syndrome: diagnosis and management. Am Fam Physician. 2007;76:405-410.
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