Merck Manual

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Turner Syndrome

(Turner's Syndrome; Monosomy X; XO Syndrome)


Nina N. Powell-Hamilton

, MD, Sidney Kimmel Medical College at Thomas Jefferson University

Reviewed/Revised Nov 2023
Topic Resources
  • Turner syndrome is caused by the deletion of part or all of one of the two X chromosomes.

  • Girls with the syndrome are typically short and with loose skin on the back of the neck, learning disabilities, and an inability to undergo puberty.

  • The diagnosis is confirmed by analyzing the chromosomes.

  • Treatment with hormones can stimulate growth and initiate puberty.

The sex chromosomes Sex chromosomes Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body or the code for functional ribonucleic... read more Sex chromosomes determine whether a fetus becomes male or female. A pair of X and Y chromosomes (XY) results in a male, and a pair of X and X chromosomes (XX) results in a female.

Worldwide, Turner syndrome occurs in about 1 out of 2,500 live female births. Almost all affected fetuses miscarry spontaneously.

Symptoms of Turner Syndrome

Some symptoms of Turner syndrome are noticeable at birth. Other symptoms are not noticed until the children are school-age or older.


Many newborns with Turner syndrome are mildly affected, but some have swelling (lymphedema Lymphedema Lymphedema is the accumulation of lymph in tissues, resulting in swelling. When lymphatic vessels are injured or obstructed, lymph fluid cannot drain and accumulates in tissues, causing swelling... read more Lymphedema ) on the backs of their hands and tops of their feet. Swelling or loose folds of skin are often evident over the back of the neck.

Other common abnormalities seen later include a webbed neck (wide skin attachment between the neck and shoulders) and a broad chest with widely spaced and inwardly turned nipples.

Older children, adolescents, and women

In most girls, the ovaries are replaced by connective tissue and do not contain developing eggs (gonadal dysgenesis), so these girls are infertile. Gonadal dysgenesis causes a lack of menstrual periods (amenorrhea Absence of Menstrual Periods Having no menstrual periods is called amenorrhea. Amenorrhea is normal in the following circumstances: Before puberty During pregnancy While breastfeeding read more ) and breast development. Girls may not go through the changes of puberty or may not complete puberty. A small number of girls do have a normal puberty and reproductive function.

Girls with Turner syndrome caused by a certain type of chromosome abnormality are at increased risk of a tumor of the ovaries called gonadoblastoma, which may be cancerous (malignant).

A girl or woman with Turner syndrome is often short compared with family members, and obesity is common.

Diagnosis of Turner Syndrome

Treatment of Turner Syndrome

  • Surgical repair of heart defects

  • Growth hormone therapy

  • Estrogen therapy

  • Regular evaluations for other problems

There is no cure for Turner syndrome. However, some specific symptoms and problems caused by the syndrome can be treated.

Coarctation of the aorta is usually repaired surgically. Doctors monitor and repair other heart defects as needed.

Lymphedema can usually be controlled with support hosiery and other techniques such as massage.

Treatment with growth hormone can stimulate growth. Once satisfactory growth has been achieved, treatment with growth hormone is stopped.

Treatment with the female hormone estrogen is usually needed to initiate puberty Puberty in Girls Puberty is a sequence of events in which physical changes occur, resulting in adult physical characteristics and capacity to reproduce. These physical changes are regulated by changes in the... read more and is typically given at age 12 to 13 but is usually not started until after satisfactory growth has been achieved. After girls have undergone puberty, they are given birth control pills that contain estrogen and progestin. These medications help girls maintain their female sexual characteristics. Estrogen therapy may also improve the girl’s ability to plan tasks, pay attention, and assess visual and spatial relationships and also helps the bones become dense and helps the skeleton develop properly.

Some girls who have Turner syndrome begin puberty normally without estrogen therapy, but this is more common among girls who are mosaic. Girls who have mosaic Turner syndrome have a mixture of two or more types of cells. Some of their cells contain two or more X chromosomes and some cells contain just one X chromosome. These people with Turner syndrome may become pregnant, and they should use contraception if they are sexually active and want to prevent pregnancy. Fertility may be limited, so if they wish to become pregnant, they usually require alternative fertility interventions.

Girls with Turner syndrome should have regular evaluations to detect problems that may result from this disorder. Evaluations include the following:

  • Heart examinations

  • Kidney function tests

  • Hearing examinations

  • Bone evaluations (for hip dislocations and scoliosis)

  • Eye examinations by a pediatric ophthalmologist

  • Thyroid function tests

  • Screening tests for celiac disease

  • Blood tests for glucose (sugar) intolerance (starting at 10 years of age)

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