Turner Syndrome

Turner syndrome (TS), also known as 45,X or 45,X0, is a genetic disorder characterised by the partial or complete absence of one X chromosome in some or all cells. This disorder primarily affects females and presents with a range of physical and physiological symptoms.

Signs and Symptoms

Physical Features

Turner syndrome manifests with distinctive physical features. Affected individuals often have a short, webbed neck, low-set ears, low hairline at the back of the neck, and swollen hands and feet at birth. Short stature is a significant characteristic, with untreated women averaging around 20 cm shorter than the general population.

Other features include a broad chest with widely spaced nipples, a high-arched palate, and lymphedema. Facial features may include a small chin, dental malocclusion, and downslanting palpebral fissures.

Cardiac and Internal Medicine

Turner syndrome is often associated with congenital heart defects, such as bicuspid aortic valves and coarctation of the aorta. These defects increase the risk of aortic dissection, a potentially fatal condition. Other common issues include hypertension, liver dysfunction, kidney anomalies, and an increased risk of type 2 diabetes.

Sensory and Autoimmune Disorders

Hearing loss, both conductive and sensorineural, is prevalent. Visual disorders, such as hyperopia, myopia, strabismus, and ptosis, are also common. Turner syndrome increases the likelihood of autoimmune conditions like Hashimoto's disease, vitiligo, and celiac disease.

Puberty and Fertility

Puberty is often delayed or absent. Most women with Turner syndrome require exogenous oestrogen to induce puberty and develop secondary sexual characteristics. Infertility is common due to primary ovarian insufficiency, though assisted reproductive technologies like donor eggs can enable pregnancy.

Diagnosis

Diagnosis can be made prenatally via amniocentesis or chorionic villus sampling, especially if abnormalities are detected on an ultrasound. Postnatally, Turner syndrome is often diagnosed based on physical signs and confirmed through a karyotype analysis.

Treatment

While there is no cure for Turner syndrome, treatments can mitigate symptoms and improve quality of life. Growth hormone therapy can help achieve a more typical height, and oestrogen replacement is used to induce and maintain secondary sexual characteristics. Surgical interventions may be necessary to address congenital heart defects or other structural anomalies. Assisted reproductive technologies are available for women who wish to become pregnant.

Epidemiology

Turner syndrome occurs in approximately 1 in 2,000 to 1 in 5,000 live female births. However, 99% of foetuses with Turner syndrome result in miscarriage or stillbirth. The syndrome was first described by Henry Turner in 1938 and later linked to chromosomal abnormalities in 1964.

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Self-assessment MCQs (single best answer)

What is another name for Turner syndrome?

Turner syndrome primarily affects which gender?

Which of the following is a common physical feature of Turner syndrome?

Which congenital heart defect is often associated with Turner syndrome?

What type of hearing loss is common in individuals with Turner syndrome?

Which condition related to puberty is often seen in women with Turner syndrome?

How is Turner syndrome typically diagnosed?

Which treatment is often used to help achieve a more typical height in Turner syndrome?

What is the approximate incidence of Turner syndrome in live female births?

Who first described Turner syndrome in 1938?