Turner Syndrome - Description

Other Names

Turner's Syndrome, Ullrich-Turner syndrome, Bonnevie-Ullrich-Turner syndrome, gonadal dysgensis, ovarian dysgenesis, XO syndrome, monosomy X

ICD-9

758.6, Turner Syndrome

Description

Turner Syndrome (TS) is a genetic condition that occurs in approximately 1/2500 live female births. TS is caused by complete or partial loss of the second sex or gender determining-chromosome.TS is characterized by short stature and ovarian insufficiency and variable presence of malformations in other organ systems including left-sided cardiac defects (particularly coarctation of the aorta and bicuspid aortic valve), lymphedema (especially nuchal, and over the dorsum of the hands and feet), short 4th metacarpals, and genitourinary malformations, such as horseshoe kidney.

Other findings characteristic of TS include: Girls with TS may have normal intelligence but are at risk for social immaturity, attention-deficit disorder and specific learning disabilities. Some combination of the above features is usually present in individuals with TS, but many affected individuals are phenotypically normal females with only short stature.

Genetics

TS occurs only in females and results from having only one normal X chromosome instead of the usual two sex chromosomes. About half of women with TS are completely missing the second sex chromosome; in others it may be partially missing or rearranged. Mosaic Turner syndrome occurs when only some of the individual’s cells lack the second normal sex chromosome. The severity of the phenotype in TS is related to the absence or presence of a second sex chromosome, with full monosomy (45,X) typically being the most severe and mosaic TS the mildest.

The risk of the same parents having a second child with TS is no greater than that of the general population (1/2500 girls).

Prognosis

Individuals with TS have a life expectancy that is approximately 13 years shorter than that of the general population, [Ostberg: 2003] but this may overestimate mortality in those who have received optimal lifelong medical care. The increased mortality risk is primarily due to congenital and atherosclerotic heart disease. Individuals with TS are also at risk for type 2 diabetes and related complications and osteoporosis. Individuals with TS are also at risk for type 2 diabetes and related complications and osteoporosis. Girls and women with TS have a small risk for fatal aortic dissection, which increases in the presence of abnormalities of the aorta or aortic valve and hypertension.

Prevalence

Turner Syndrome is present in approximately 1/2500 live female births worldwide. It is more common in pregnancies that don’t survive to term, such as miscarriages and stillbirths. Some believe that >99% of pregnancies affected by TS result in spontaneous miscarriage.

Impact

Individuals with TS can have life-threatening physical manifestations (cardiovascular & lymphatic anomalies), manifestations that impart significant psycho-emotional burden (short stature, absence of puberty, and sterility) and a higher relative risk for a number of co-morbidities that are detailed later in this module.

Helpful Articles

PubMed search for articles on Turner Syndrome in children for the last 3 years.

Loscalzo ML.
Turner syndrome.
Pediatr Rev. 2008;29(7):219-27. PubMed abstract
This review focuses on the diagnosis of Turner Syndrome as well as associated complications.

Bondy CA.
Care of girls and women with Turner syndrome: A guideline of the Turner Syndrome Study Group.
J Clin Endocrinol Metab. 2007;92(1):10-25. PubMed abstract
This clinical practice guideline uses evidence-based data when available; expert opinion was used when evidence was lacking. It is a comprehensive review of the diagnosis of Turner Syndrome as well as the management of associated complications.

Sybert VP, McCauley E.
Turner's syndrome.
N Engl J Med. 2004;351(12):1227-38. PubMed abstract / Full Text

Turner Syndrome Module Authors

Authors: Vandana Raman, MD - 10/2011
Alan F. Rope, MD - 9/2011
Catherine Jolma, MD - 9/2009
Content Last Updated: 10/2011

The authors listed above are responsible for the overall Turner Syndrome Module. Authors contributing to individual pages in the module are listed on those pages.

Page Bibliography

Ostberg JE, Conway GS.
Adulthood in women with Turner syndrome.
Horm Res. 2003;59(5):211-21. PubMed abstract