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Turner syndrome


Other Names for this Disease

  • 45, X Syndrome
  • Bonnevie-Ulrich syndrome
  • Chromosome X Monosomy X
  • Gonadal Dysgenesis (45,X)
  • Schereshevkii Turner Syndrome
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Overview

What is Turner syndrome?

What are the signs and symptoms of Turner syndrome?

What causes Turner syndrome?

What is Turner syndrome?

Turner syndrome is a chromosomal disorder that usually affects development in females.[1] Symptoms differ among individuals, but may include shortened stature, infertility, extra skin on the neck (webbed neck), puffiness or swelling (lymphedema) of the hands and feet, skeletal abnormalities, heart defects, and kidney problems.[2] Females without Turner syndrome have 2 full X chromosomes in each of their cells. An individual with Turner syndrome is missing all or part of one X chromosome. Although it is genetic, it is typically not inherited. Treatment may include growth hormone therapy for short stature and estrogen therapy to help stimulate sexual development. Assisted reproduction techniques can help some women with Turner syndrome become pregnant.[3]
Last updated: 6/18/2012

What are the signs and symptoms of Turner syndrome?

There are various signs and symptoms of Turner syndrome, and they can range from very mild to more severe among individuals with the condition. Girls who have Turner syndrome are typically shorter than average. They often have normal height for the first three years of life, but then have a slow growth rate. In early childhood, individuals may have frequent middle ear infections, which can lead to hearing loss in some cases. At puberty, they do not have the usual growth spurt, and the ovaries do not function properly (they do not begin to produce sex hormones). Therefore, most girls with Turner syndrome do not start their periods or develop breasts without hormone treatment. Although most individuals with Turner syndrome are infertile, the vagina and uterus are usually normal. Individuals with Turner Syndrome usually have normal intelligence with good verbal skills and reading skills. Some girls, however, have problems with math, memory skills and fine-finger movements.

Additional symptoms of Turner syndrome may include a very wide neck (webbed neck) and a low or indistinct hairline; broad chest and widely spaced nipples; arms that turn out slightly at the elbow; heart murmur, sometimes associated with narrowing of the aorta (blood vessel exiting the heart); tendency to develop high blood pressure; and minor eye problems that may be corrected by glasses. Scoliosis (curving of the spine) occurs in 10 percent of adolescent girls who have Turner syndrome. Additionally, the thyroid gland becomes under-active in about 10 percent of women with the condition. Older or over-weight women with Turner syndrome are slightly more at risk of developing diabetes. Osteoporosis can develop due to a lack of estrogen, but this can usually be prevented by taking hormone replacement therapy.[1]
Last updated: 12/15/2010

What causes Turner syndrome?

Turner syndrome is a condition caused by partial or complete loss of one of the X chromosomes in females. Females typically have 2 full X chromosome in all of their cells, while males have one X chromosome and one Y chromosome.[4]

Most females with Turner syndrome are missing a full X chromosome in all of their cells (called monosomy X).[5] This is thought to occur due to an error in cell division prior to conception called nondisjunction, which results in egg or sperm cells (germ cells) with an abnormal number of chromosomes. If one of these germ cells is missing an X chromosome and contributes to the genetic makeup of a child, the child will have a single X chromosome in each cell and will be missing the other sex chromosome.[2]

Some females with Turner syndrome have both X chromosomes, but one of the X chromosomes has a deletion.[5] A deletion may occur sporadically (for the first time in the affected individual) or be inherited from a parent. This is sometimes called partial Turner syndrome. The signs and symptoms of partial Turner syndrome can vary widely depending on the size of the missing portion as well as the specific genes that are missing. Generally, larger deletions cause more signs and symptoms than smaller deletions.[4] It is also possible for an individual with Turner syndrome to be missing all or part of one X chromosome in only some of her cells, which is called mosaicism. This may be referred to as mosaic Turner syndrome. Mosaic Turner syndrome is typically caused by a random error in cell division that occurs shortly after conception.[5]
Last updated: 6/25/2012

References
  1. Learning About Turner Syndrome. National Human Genome Research Institute. June 28, 2010; http://www.genome.gov/19519119. Accessed 12/14/2010.
  2. Turner syndrome. Genetics Home Reference. September 2005; http://ghr.nlm.nih.gov/condition=turnersyndrome. Accessed 4/7/2008.
  3. Turner syndrome. MedlinePlus. December 4, 2010; http://www.nlm.nih.gov/medlineplus/turnersyndrome.html. Accessed 12/14/2010.
  4. Genetic Features of Turner Syndrome. National Institute of Child Health and Human Development (NICHD) . September 27, 2004; http://turners.nichd.nih.gov/genetic.html. Accessed 8/8/2008.
  5. Learning About Turner Syndrome. National Human Genome Research Institute (NHGRI). November 27, 2007; http://www.genome.gov/19519119. Accessed 4/7/2008.


Other Names for this Disease
  • 45, X Syndrome
  • Bonnevie-Ulrich syndrome
  • Chromosome X Monosomy X
  • Gonadal Dysgenesis (45,X)
  • Schereshevkii Turner Syndrome
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.