Turner Syndrome

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(Monosomy X)

Definition

Turner syndrome is a genetic disorder that consists of a broad spectrum of features that vary in individuals, but usually have the common findings of short stature (average adult height: 4 feet 8 inches) and loss of ovarian function. The loss of ovarian function usually leads to infertility and inhibited sexual development.

Causes

Turner syndrome only occurs in girls and women. Females normally have two X chromosomes. Chromosomes are hereditary material in each cell of the body, that determine characteristics like gender and height. Turner syndrome is most commonly caused by a missing X chromosome. It affects 1 out of 2,000 live female births. It is usually sporadic, meaning that it is not inherited from a parent. In rare cases, a parent silently carries rearranged chromosomes that can result in Turner syndrome in a daughter; this is the only situation in which Turner syndrome is inherited.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. There are no known risk factors for Turner syndrome, other than being female.

Symptoms

There are many possible manifestations of this syndrome, but the main features include:
  • Short stature—if the disorder is not treated, the average adult is about 4 feet 8 inches tall.
  • Lack of development of the ovaries—the ovaries are the organs that produce eggs for fertilization and female hormones. Most girls with Turner syndrome do not start puberty. Many do not have normal breast development or menstrual periods. Most cannot produce eggs and as a result, are infertile.
Fully Developed Female Reproductive System
Female Reproductive Organs
Copyright © Nucleus Medical Media, Inc.
Other physical features can include:
  • Webbed neck
  • Low hairline in back
  • Abnormal eye features (drooping of eyelids)
  • Abnormal bone development, for example a 'shield-shaped', broad, flat chest
  • Absent or delayed development of secondary sexual characteristics that normally appear at puberty, including sparse pubic hair, small breasts
  • Infertility
  • Decreased tearing
  • Absent menstruation
  • A single crease in the palm
  • Absence of normal moisture in vagina
  • Painful intercourse
  • Flat feet
  • Swelling (edema) of the hands and feet (mostly noted at time of birth)
Other health conditions that can occur include:
  • High blood pressure, even in childhood
  • Structural heart abnormalities
  • Kidney problems
  • Thyroid problems
  • Osteoporosis , which can lead to height loss, curved spine, and broken bones
  • Hearing and other ear problems
  • Impaired sense of visual coordination despite normal intelligence
  • Celiac disease
  • Increased risk for cancer

Diagnosis

Depending on its severity, Turner syndrome may first be diagnosed in infancy, childhood, or adolescence.
  • The doctor asks about the symptoms and medical history, and performs a physical exam. Gynecologic exam may reveal dry vaginal lining.
  • Ultrasound may reveal small or underdeveloped female reproductive organs.
  • Genetic testing in the form of a blood test called a karyotype is used to examine the chromosomes for a missing X chromosome. This is the definitive diagnostic procedure.

Treatment

There is no known cure for Turner syndrome. However, there are treatments for many of the associated problems. These include:

Growth Hormone

If given early enough in childhood, growth hormone can improve growth and increase final adult height by a few inches. However, not all children have a good response to growth hormone. Bone-lengthening surgery can increase the final height of children with Turner syndrome who have not responded adequately to growth hormone. However, this lengthy treatment requires multiple surgeries, long periods of disability, and risks many potential complications.

Estrogen Replacement Therapy

Estrogen replacement therapy induces the normal physical changes of adolescence, including breast growth and menstrual periods. Women with Turner syndrome usually take estrogen-progesterone treatment until at least menopause to protect their bones from osteoporosis.

Treatment for Other Medical Conditions

Other medical problems are carefully monitored and treated, including:
From 5%-10% of children with Turner syndrome are found to have a severe constriction of the major blood vessel coming out from the heart, a condition known as "coarctation of the aorta". This can be surgically corrected as soon as it is diagnosed.
Doctors have identified a serious condition called aortic dissection (bleeding in the wall of aorta) as being a cause of death in women with Turner syndrome.
As many as 15% of adults with Turner syndrome are reported to have "bicuspid aortic valves," meaning that the major blood vessel from the heart has only two rather than three components to the valve regulating blood flow. It requires careful medical monitoring, since bicuspid aortic valves can deteriorate or become infected. In general, it is advised that all persons with Turner syndrome undergo annual cardiac evaluations.
In the absence of severe heart defects at birth, women survive into adulthood with normal intelligence. However, girls and women with Turner syndrome may have difficulty with specific visual-spatial coordination tasks (eg, mentally rotating objects in space) and learning math (geometry, arithmetic).
Other recommendations for life-long management of this disorder include:
  • Cardiac evaluation including both echocardiography and magnetic resonance angiography should be performed.
  • Puberty should be induced at an age-appropriate time and should not be delayed in hopes of achieving greater adult height.
  • Comprehensive psychological evaluation should be done to detect learning disorders.
  • Lifetime surveillance should be carried out looking for hearing problems, thyroid disease, hypertension , diabetes, and cholesterol elevation.

Prevention

There are no guidelines for preventing Turner syndrome.

RESOURCES

American Academy of Pediatrics http://www.aap.org/

Turner Syndrome Society of the United States http://www.turnersyndrome.org/

CANADIAN RESOURCES

Caring for Kids The Canadian Paediatric Society http://www.caringforkids.cps.ca/

Turner's Syndrome Society of Canada http://www.turnersyndrome.ca/

References

Bondy C. Care of girls and women with Turner syndrome: a guideline of the Turner syndrome study group. J Clin Endocrinol Metab. 2006 Oct 25. Available at http://jcem.endojournals.org/cgi/rapidpdf/jc.2006-1374v1.

Hahn SB, Park HW, Park HJ, Seo YJ, Kim HW. Lower limb lengthening in Turner dwarfism. Yonsei Med J . 2003 Jun 30;44(3):502-7.

National Institute of Child Health and Human Development website. Available at: http://turners.nichd.nih.gov/ClinFrIntro.html .

The Nemours Foundation website. Available at: http://www.nemours.org/index.html .

Turner Syndrome. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Updated August 2010. Accessed October 25, 2010.

Turner Syndrome Society website. Available at: http://www.turnersyndrome.org .

Revision Information

  • Reviewer: Kari Kassir, MD
  • Review Date: 09/2012 -
  • Update Date: 00/91/2012 -

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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