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

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.

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

Turner syndrome can be diagnosed at any stage of life. It may be diagnosed before birth 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 (heart ultrasound)
• Karyotyping (chromosome analysis)
• 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.