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Magill’s Medical Guide, 9th Edition

Turner syndrome

by Clara Abouelsaad, , OMS-III

Category: Disease/Disorder

Also known as: Gonadal dysgenesis, Bonnevie-Ullrich syndrome, monosomy X

Anatomy or system affected: Cells, endocrine system, reproductive system

Specialties and related fields: Endocrinology, genetics, gynecology, obstetrics

Definition: A genetic condition in which cells are missing all or part of an X chromosome.

CAUSES AND SYMPTOMS

Turner syndrome affects an estimated one out of every 2500 to 5000 live female births. The disorder is congenital, which means that it begins at conception. Normal males have one X and one Y chromosome. Normal females have two X chromosomes. Females with Turner syndrome have only one X chromosome (an XO pattern) in each of their cells or two X chromosomes with one being incomplete. Some patients are monosomy (45,X) where they only have one X chromosome. A smaller percentage of patients have mosaicism in which some sets of cells in their body have two X chromosomes and others have only one. Some patients have structural abnormalities in an X chromosome. In rare cases, some patients may present with a Y chromosome in their genome. In the majority of patients, the missing X chromosome is from the father. This syndrome is the most common sex chromosome abnormality found in spontaneous abortions, accounting for 20 percent. Although the exact cause is unknown, scientists believe that the disorder may result from an error during the division of the parent’s sex cells.

Shortness is the most common feature of Turner syndrome. The average height of a woman with this condition is 4 feet, 8 inches. Short stature is due to short stature homeobox (SHOX) gene deletions. Other physical features associated with the syndrome include puffy hands and feet at birth, a webbed neck, prominent ears, a low hairline at the back of the neck, drooping eyelids, dry eyes, flat and broad chest with widely spaced nipples, soft fingernails that turn up at the end, and vaginal dryness. Females with Turner syndrome may go unrecognized if the only presenting feature is short stature. Prenatal screening findings that may aid in the diagnosis of Turner syndrome include nuchal cystic hygroma, fetal edema, a murmur indicating left-sided cardiac defect, and short limbs. Dysmorphic facial features including ptosis, hypertelorism, up-slanting palpebral fissures, epicanthal folds, flat nasal bridge, low-set ears, and a high-arched palate may also be clinical manifestations. In the extremities, females may present with edema, nail hypoplasia, short fourth metacarpal, cubitus valgus, and many pigmented nevi. The presence of edema is due to the failure of lymph absorption by the lymphatic capillaries, producing the clinical manifestation of nuchal cystic hygromas, webbed neck, and edematous extremities.

Information on Turner Syndrome

Causes: Genetic defect

Symptoms: Short stature, puffy hands and feet at birth, webbed neck, prominent ears, soft fingernails that turn up at end, ovarian failure leading to infertility and incomplete sexual development, cardiovascular problems

Duration: Chronic

Treatments: Hormonal therapy for some symptoms

There are various congenital abnormalities associated with Turner syndrome. This syndrome is found to be under a bigger classification of premature ovarian insufficiency, where gonadal failure is found in the majority of patients, due to ovarian dysgenesis. This is due to the presence of streak ovaries because there is very little connective tissue with few or no ovarian follicles. Cardiac abnormalities vary with findings such as bicuspid aortic valve, aortic coarctation, elongated transverse aortic arch, and aortic stenosis. Renal structural findings include horseshoe kidney and collecting-system abnormalities. Patients can also have musculoskeletal abnormalities such as congenital hip dislocations, scoliosis, kyphosis, and wrist deformities. Ophthalmologic findings such as strabismus and hyperopia are other clinical manifestations.

Ovaries may or may not develop in those with Turner syndrome, and most patients experience ovarian failure. Since the ovaries normally produce estrogen, girls and women with Turner syndrome lack this essential hormone, resulting in infertility, incomplete sexual development, and increased risk of osteoporosis. Cardiovascular disorders are the single source of increased mortality in patients with Turner syndrome with causes such as aortic dissection or rupture. Women with Turner syndrome are at higher risk of hypertension, renal abnormalities, sensorineural hearing loss, cataracts, and several autoimmune disorders such as thyroid disease (hypothyroidism and hyperthyroidism), diabetes, celiac disease, alopecia areata, uveitis, rheumatoid arthritis, and inflammatory bowel disease. Hashimoto thyroiditis is shown to be the most common autoimmune disorder associated with Turner syndrome. It is thought to be due to a decrease in lymphocytes, altering the immune system in protecting the host. Obesity is prevalent in patients with Turner syndrome, exhibiting higher body mass index (BMI), percent body fat, bigger waist circumference, and lower percent lean body mass than others in the general population.

TREATMENT AND THERAPY

Antenatal diagnosis of Turner syndrome is made through ultrasound identification of a cystic hygroma and pleural effusion. Chromosomal karyotype is the gold standard in confirming the diagnosis of Turner syndrome. However, no treatment is available to correct the chromosome abnormality that causes this condition. Nevertheless, early injections of human growth hormone can restore much of the growth deficit, and is especially indicated for patients below the fifth percentile in growth. Low-dose oxandrolone can be used as an adjunctive therapy with growth hormone.

Unless they take hormone therapy, women and girls with Turner syndrome will not menstruate or develop breasts and pubic hair. Estrogen therapy is started at adolescence, reducing the risk of bone loss and atherosclerosis. Although infertility cannot be altered, pregnancy may be possible through in vitro fertilization. All patients are referred to a cardiologist for regular follow-up with an electrocardiogram (ECG) and cardiac imaging. Other specialists involved in the care of these patients include obstetrician-gynecologists in managing infertility, endocrinologists for growth management, ophthalmologists, audiologists, and nephrologists. In cases where a Y chromosome is present, gonadectomy is performed to decrease the risk of gonadoblastoma. Girls and women with Turner syndrome require an interdisciplinary team and should be monitored and treated for associated conditions.

In addition to medical management, psychological and educational support are also important in management of this syndrome. Learning disabilities are found in 70 percent of patients, and they can present with motor or visuospatial abnormalities. Intellectual disability is found in 6 percent of patients, with most patients having normal intelligence.

PERSPECTIVE AND PROSPECTS

Henry Turner first identified Turner syndrome in 1938. In 1959, C. E. Ford discovered that a chromosomal abnormality involving sex chromosomes causes the syndrome. Further chromosomal research indicated that Turner syndrome was defined as the presence of one functioning X chromosome. Many advancements in research involved the SHOX gene’s role in Turner syndrome. This gene was originally identified in patients with short statures who had deletions present on the short arm of the X chromosome. In the recent years, the molecular functions of SHOX and its role in the skeletal phenotypes, such as short metacarpals, cubitus valgus, and high arched palate, in Turner syndrome continues to be investigated. In addition to the SHOX gene, other genes have been discovered to play a role in the pathogenesis of this syndrome, more specifically their role in the various organ systems that are affected in these patients. Ongoing research is focused on exploring the constitution of the X and Y chromosomes and their role in human development and disease, which can help to guide medical management for patients.

See also: Dwarfism; Endocrine system; Endocrinology; Endocrinology, pediatric; Genital disorders, female; Genetic diseases; Genetics and inheritance; Growth; Hormone therapy; Hormones; Infertility, female; Menstruation; Ovaries; Puberty and adolescence; Reproductive system; Sexual differentiation; Women’s health.

For Further Information:

1 

A.D.A.M. Medical Encyclopedia. “Turner Syndrome.” MedlinePlus, 30 Mar. 2012.

2 

Behrman, Richard E., et al. Nelson Textbook of Pediatrics. Elsevier Inc., 2020.

3 

Ferri, Fred F. Ferri’s Clinical Advisor. Elsevier, 2022.

4 

Gravholt, Claus H., et al. “Clinical Practice Guidelines for the Care of Girls and Women with Turner Syndrome: Proceedings from the 2016 Cincinnati International Turner Syndrome Meeting.” European Journal of Endocrinology, vol. 177, no. 3, 2017, doi.org/10.1530/eje-17-0430.

5 

Henry, Helen L., and Anthony W. Norman, editors. Encyclopedia of Hormones. 3 vols., Academic Press, 2003.

6 

Kronenberg, Henry M., et al., editors. Williams Textbook of Endocrinology. 12th ed., Saunders/Elsevier, 2011.

7 

Lewis, Ricki. Human Genetics: Concepts and Applications. 10th ed., McGraw-Hill, 2012.

8 

Martin, Richard J., et al. Fanaroff and Martin’s Neonatal-Perinatal Medicine: Diseases of the Fetus and Infant. Elsevier, 2020.

9 

Milunsky, Aubrey, editor. Genetic Disorders and the Fetus: Diagnosis, Prevention, and Treatment. 5th ed., Johns Hopkins UP, 2004.

10 

Money, John. Sex Errors of the Body and Related Syndromes: A Guide to Counseling Children, Adolescents, and Their Families. 2nd ed., Paul H. Brookes, 1994.

11 

National Institute of Child Health and Human Development. “Turner Syndrome: Condition Information.” US Department of Health and Human Services. National Institutes of Health, 30 Nov. 2012.

12 

Partin, Alan W. Campbell-Walsh-Wein Urology. Elsevier, 2021.

13 

Pinsky, Leonard, Robert P. Erickson, and R. Neil Schimke. Genetic Disorders of Human Sexual Development. Oxford UP, 1999.

14 

Rosenblum, Laurie, and Kari Kassir. “Turner Syndrome.” Health Library, 12 Sept. 2012.

15 

Rosenfeld, Ron G., and Melvin M. Grumbach, editors. Turner Syndrome. Marcel Dekker, 1990.

16 

San Roman, Adrianna K., and David C. Page. “A Strategic Research Alliance: Turner Syndrome and Sex Differences.” American Journal of Medical Genetics Part C: Seminars in Medical Genetics, vol. 181, no. 1, Mar. 2019, pp. 59-67, doi.org/10.1002/ajmg.c.31677.

17 

Wang, Hao, et al. “Bioinformatic Analysis Identifies Potential Key Genes in the Pathogenesis of Turner Syndrome.” Frontiers in Endocrinology, vol. 11, 2020, doi.org/10.3389/fendo.2020.00104.

18 

“What Is TS?” Turner Syndrome Society of the United States, 2011.

Citation Types

Type
Format
MLA 9th
Abouelsaad, Clara. "Turner Syndrome." Magill’s Medical Guide, 9th Edition, edited by Anubhav Agarwal,, Salem Press, 2022. Salem Online, online.salempress.com/articleDetails.do?articleName=MMG2022_1403.
APA 7th
Abouelsaad, C. (2022). Turner syndrome. In A. Agarwal, (Ed.), Magill’s Medical Guide, 9th Edition. Salem Press. online.salempress.com.
CMOS 17th
Abouelsaad, Clara. "Turner Syndrome." Edited by Anubhav Agarwal,. Magill’s Medical Guide, 9th Edition. Hackensack: Salem Press, 2022. Accessed October 22, 2025. online.salempress.com.