Definition of Turner syndrome:

Turner syndrome is a genetic condition in which a female does not have the usual pair of two X chromosomes.

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.

Symptoms:

Possible symptoms in young infants include:

• Swollen hands and feet
• Wide and webbed neck

A combination of the following symptoms may be seen in older females:

• Absent or incomplete development at puberty, including sparse pubic hair and small breasts
• Broad, flat chest shaped like a shield
• Drooping eyelids
• Dry eyes
• Infertility
• No periods (absent menstruation)
• Short height
• Vaginal dryness, can lead to painful intercourse

Signs and tests:

Turner syndrome can be diagnosed at any stage of life. It may be diagnosed before birth if chromosome analysis 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:

• Blood hormone levels (luteinizing hormone and follicle stimulating hormone)
• Echocardiogram
• Karyotyping
• MRI of the chest
• Ultrasound of reproductive organs and kidneys
• Pelvic exam

Turner syndrome may also alter various estrogen levels in the blood and urine.

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:

• Arthritis
• Cataracts
• Diabetes
• Hashimoto's thyroiditis
• Heart defects
• High blood pressure
• Kidney problems
• Middle ear infections
• Obesity
• Scoliosis (in adolescence)

Prevention:

There is no known way to prevent Turner syndrome.