Turner syndrome
Definition
Turner syndrome is a genetic condition that occurs only in females. Female cells normally have two X chromosomes. In Turner syndrome, cells are missing all or part of an X chromosome.
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 have two of the same sex chromosomes, written as XX. Males have an X and a Y chromosome (written as XY).
In Turner syndrome, a female does not have the usual pair of two complete X chromosomes. 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.
Symptoms
Possible symptoms include a combination of:
Signs and tests
Turner syndrome can be diagnosed at any stage of life. It may be diagnosed before birth if karyotyping is done during prenatal testing.
The doctor will perform a physical exam and look for signs of underdevelopment. Infants with Turner syndrome often have swollen hands and feet.
The following tests may be performed:
Turner syndrome may also alter the results of the following tests:
Treatment
Growth hormone may help a child with Turner syndrome grow taller. Estrogen replacement therapy is often started when the girl is 12 or 13 years old. This helps trigger the growth of breasts, pubic hair, and other sexual characteristics.
Women with Turner syndrome who wish to become pregnant may consider using a donor egg.
Support Groups
For additional information and resources, see:
Turner Syndrome Society -- www.turnersyndrome.org
Expectations (prognosis)
Those with Turner syndrome can have a normal life when carefully monitored by their doctor.
Complications
Prevention
There is no known way to prevent Turner syndrome.
Review Date: 12/11/2006
Reviewed By: Brian Kirmse, MD, Mount Sinai School of Medicine, Department of Human Genetics, New York, NY. Review provided by VeriMed Healthcare Network.
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