Turner Syndrome

Turner syndrome is a genetic disorder caused by a missing or partially missing X chromosome. It affects only females and typically causes a variety of physical abnormalities. Girls and women with Turner syndrome are usually short, their ovaries and breasts fail to develop normally, and they are almost always infertile.

What Is Turner Syndrome?

Turner syndrome is a genetic disorder that occurs when one of a girl's X chromosomes is partially or completely missing. Almost every cell in a person's body (except for eggs and sperm cells) has 23 pairs of chromosomes. One pair, the sex chromosomes, makes a person male or female: boys have an X and a Y chromosome (XY), whereas girls have two X chromosomes (XX). The chromosomes contain all of the information the body needs to function and to develop properly. If part of a chromosome is missing, as in Turner syndrome, the important information on that chromosome is also missing.

Turner syndrome (also called X0 syndrome) is a chromosomal condition where females are missing one (or part of one) of their two X chromosome copies.

Turner syndrome (also called X0 syndrome) is a chromosomal condition where females are missing one (or part of one) of their two X chromosome copies. Most commonly, an individual with Turner syndrome will be born with 45 chromosomes in each cell rather than 46. The missing chromosome is an X chromosome (shown in the illustration as XO).
Alila Medical Media/Shutterstock.com.

How a girl's body is affected physically by Turner syndrome depends on how much of the chromosome is missing. Some girls have a mild form of the syndrome that is not detected until they are teenagers or adults. If untreated, nearly all girls with Turner syndrome grow slowly and reach a short adult height, their breasts do not enlarge, and they do not have menstrual periods as is normal for adolescent girls. Osteoporosis and fractures are also common in women with Turner syndrome. In some women, bone density can approach normal levels after treatment with estrogen (hormone) therapy. Some may have additional problems, including the following:

Most of the physical conditions are treatable, and with good consistent medical care, a person with Turner syndrome can have a fully productive life and normal life span. Most people with Turner syndrome have normal intelligence, but some may have specific learning problems, especially with math.

It is believed that approximately 98 percent of pregnancies in which the mother is carrying a fetus with the genetic defect that would become Turner syndrome will spontaneously end in miscarriage * .

What Causes Turner Syndrome?

Living with Turner Syndrome: Carol's Life

Because of physical abnormalities and feeling “different,” life might not be easy for a girl with Turner syndrome. Carol was born with swollen hands and feet, extra skin at the back of her neck (a webbed neck), oddly shaped ears, and arms that tilted outward from the elbows. Based on her appearance, her doctor suspected that she had Turner syndrome. A test in which Carol's chromosomes were studied confirmed that she was missing one of her X chromosomes.

Carol was teased about her appearance in elementary school, but she was most miserable during her teenage years. She was the shortest person in her class. When other girls started developing breasts and getting their period, Carol still looked and felt like a little girl. After Carol's doctor prescribed the hormone estrogen to promote sexual development, she finally got her period.

How Do Doctors Treat Turner Syndrome?

Many of the problems associated with Turner syndrome, such as the failure of the ovaries to develop normally, cannot be prevented, but there are a number of medical treatments that can be performed to improve an affected person's quality of life:

See also Chronic Illness • Genetic Diseases: Overview • Growth and Growth Disorders • Infertility • Menstruation and Menstrual Disorders • Puberty and Sexual Development


Books and Articles

Folsom, L. J., and J. S. Fuqua. “Reproductive Issues in Women with Turner Syndrome.” Endocrinology and Metabolism Clinics of North America 44 (2015): 723–37.


Centers for Disease Control and Prevention. “Family Health History and Genetics.” http://www.cdc.gov/ncbddd/genetics/index.html (accessed March 1, 2016).

MedlinePlus. “Turner Syndrome.” U.S. National Library of Medicine. https://www.nlm.nih.gov/medlineplus/turnersyndrome.html (accessed March 1, 2016).

National Organization for Rare Disorders. “Turner Syndrome.” https://rarediseases.org/rare-diseases/turner-syndrome/ (accessed March 1, 2016).


Eunice Kennedy Shriver National Institute of Child Health and Human Development. 10 Center Dr., CRC 1-3330, Bethesda, MD 20892-1103. Telephone: 301-496-7731 Website: http://turners.nichd.nih.gov (accessed March 1, 2016).

National Organization for Rare Disorders. 55 Kenosia Ave., Danbury, CT 06810. Telephone: 203-744-0100. Website: https://rarediseases.org (accessed March 1, 2016).

Turner Syndrome Society of the United States. 11250 West Rd., Ste. G, Houston, TX 77065. Telephone: 832-912-6006. Website: http://www.turnersyndrome.org/ (accessed March 1, 2016).

* miscarriage (MIS-kare-ij) is the end of a pregnancy through the death of the embryo or fetus before birth.

  This information is not a tool for self-diagnosis or a substitute for professional care.