What Is Turner Syndrome? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Turner syndrome is a condition in which a woman is missing all or part of one X chromosome.

Normally, people have two sex chromosomes in each cell: Females have two X chromosomes, and males have an X and a Y.

But in Turner syndrome, one normal X chromosome is present, and the other X chromosome is nonfunctioning because it is missing, partially missing, or rearranged.

It’s also possible for a person with Turner syndrome to have what’s known as chromosomal mosaicism, or mosaic Turner syndrome, in which some cells have the normal number of X chromosomes and some do not.

Turner syndrome is considered a rare condition, estimated to occur in about 1 of every 2,000 to 2,500 live female births.

It’s named after Henry Turner, the American endocrinologist who first described the syndrome in 1938, and is also referred to as Ullrich-Turner syndrome, gonadal dysgenesis, or congenital ovarian hypoplasia.

Turner syndrome is associated with a wide variety of physical characteristics, but not all of the characteristics are present in every individual who has it. The most common features of Turner syndrome are short stature and lack of puberty, because the ovaries do not develop normally. (1,2)

Prenatal ultrasound of a baby with Turner syndrome may show:

• Significant fluid collection on the back of the neck
• Heart abnormalities
• Kidney abnormalities

Signs or symptoms of Turner syndrome at birth or during infancy include:

• Below-average length at birth
• Delayed growth
• Poorly developed toenails and fingernails
• A high-arched palate
• Forearms that angle away from the body (called cubitus valgus)
• Prominent, low-set ears
• A low hairline at the back of the head
• A small or receding chin
• Folds of skin at the base of the neck or a webbed neck
• Droopy eyelids
• Multiple moles
• Kyphosis (rounded spine)
• Scoliosis (curvature of the spine)
• Flat feet
• Epicanthal folds (in which the skin of the upper eyelid covers the inner corners of the eyes)
• Strabismus (in which the eyes don’t align properly)

The ovaries of girls and women with Turner syndrome usually do not contain eggs, making most affected women infertile.

However, it’s possible for women with Turner syndrome to bear children using donated eggs and in vitro fertilization. (3)

Turner syndrome can also cause cardiovascular defects, especially defects of the aorta (the main artery pumping blood from the heart).

Cardiovascular abnormalities are the leading cause of death among individuals with Turner syndrome.

Turner syndrome is also associated with kidney abnormalities, high blood pressure, diabetes, thyroid disease, and hearing loss. Less commonly, abnormal blood vessels in the intestines may cause bleeding.

Most girls and women with Turner syndrome are of normal intelligence, but neurocognitive defects and abnormal visuospatial coordination can cause learning disabilities, especially involving calculations, memory, and attention.

While Turner syndrome is considered a genetic disorder, most cases are not inherited. (1)

A missing X chromosome results from a random event during the formation of the eggs or sperm in one of the parents of the affected person. This is called monosomy Turner syndrome.

Mosaic Turner syndrome results from a random event during cell division in early fetal development. As a result, some cells in the body of the affected person have two complete copies of the X chromosome, while other cells have only one copy.

In cases of Turner syndrome caused by a partial deletion of the X chromosome, cells have one complete and one altered copy of the chromosome. This error can occur in the father’s sperm or the mother’s egg, or as a result of cell division in early fetal development.

It's possible, but rare, for this form of the genetic defect to be passed from one generation to the next.

A small percentage of women with Turner syndrome have some cells with one copy of the X chromosome and others have one copy of the X chromosome and some Y chromosome material. Women with this form of the condition will develop biologically as female, but the presence of Y chromosome material increases their risk for developing a type of tumor called gonadoblastoma.

In general, though, the physical characteristics and health complications that arise for women with these chromosomal errors vary from person to person.

Risk Factors for Turner Syndrome

The loss or alteration of the X chromosome that causes Turner syndrome occurs randomly — sometimes as a result of problems with the father’s sperm or the mother’s egg and, for others, as a result of something that happens early in fetal development.

In general, it’s unlikely that parents of one child with Turner syndrome will have another child with the disorder, or that any family history of the condition increases a person’s risk for developing it.

If your doctor suspects that your child has Turner syndrome, a genetic test will typically be done to analyze their chromosomes. (4)

This test is usually done with a blood sample, although your doctor may take a cheek scraping (buccal smear) or skin sample.

The test determines whether or not your child’s cells are missing an X chromosome or have one or more abnormal X chromosomes.

However, the age at which a diagnosis is made varies widely from person to person, due to mild symptoms in some individuals.

A diagnosis may be made prenatally, or it may be made at birth if symptoms such as swelling of the hands and feet or loose folds of skin at the back of the neck are present.

A diagnosis of Turner syndrome may also occur in childhood, if a girl is not growing as much or as rapidly as expected, or it may be made in adolescence, if a girl is very short or is not going through puberty by her teen years.

For some women, diagnosis comes in adulthood, as a consequence of premature ovarian failure or early menopause. (2)

And some women with Turner syndrome are never diagnosed with it if they have only mild features of the syndrome.

Prenatal Testing for Turner Syndrome

Your doctor can perform one of two tests to make a diagnosis before your baby’s birth:

• Chorionic villus sampling (CVS)
• Amniocentesis

Chorionic villus sampling involves taking a small piece of tissue from the placenta, which contains the same genetic material as the baby and can be analyzed to identify errors in chromosomes. CVS can be done earlier than amniocentesis, but it is not as accurate.

In amniocentesis, a sample of the amniotic fluid is taken from the uterus and tested to analyze the baby’s chromosomes.

Both of these tests carry some risk to the mother and the baby, which you should discuss with your doctor before having either one of them done.

Prognosis of Turner Syndrome

The long-term prognosis for women with Turner syndrome is generally positive, according to the Genetic and Rare Diseases Information Center of the National Institutes of Health. (5)

Research suggests that life expectancy for women with the condition is slightly shorter than average (which is 78.6 years in the United States, according to the Centers for Disease Control and Prevention). (6) However, proactively managing related chronic conditions such as diabetes, high blood pressure, and obesity can help.

Most women with Turner syndrome die as a result of related conditions for which they are at increased risk, including heart disease and some forms of cancer. (7)

In addition, regular checkups and hormone therapy have shown substantial improvements in the quality and length of life for women with Turner syndrome, according to the Mayo Clinic. (4)

Turner syndrome affects different women in different ways. The condition is typically diagnosed before birth or shortly after birth, or during early childhood, but it may go undiagnosed in some women well into adulthood. (2)

However, once diagnosed, women with Turner syndrome must manage its symptoms and complications for the rest of their lives. Women with Turner syndrome can potentially develop a wide variety of health problems affecting many different organ systems — including the eyes, heart, kidneys, and digestive tract.

There’s no cure for Turner syndrome, or any proven treatment for the condition itself. However, some medications can help address some of its complications. (2,4)

Medication Options

The use of growth hormone in childhood — given daily by injection — can stimulate growth and help a girl achieve a more normal adult height.

Starting growth hormone treatment early can improve height and bone growth. The average height of women with Turner syndrome who did not receive growth hormone is 4 feet 8 inches. Growth hormone therapy increases adult height by 4 inches, on average.

In some girls with below-average height, a doctor may recommend oxandrolone as well as growth hormone. Oxandrolone is a hormone that increases the body’s production of protein and increases bone mineral density.

In addition, estrogen and progesterone therapy can stimulate sexual maturation and also improve the symptoms causing learning difficulties. Estrogen therapy also helps to promote breast development and increase the size (volume) of the uterus, and it can also boost bone mineralization.

Most girls with Turner syndrome start estrogen and related hormone therapy at around age 12 or 14 so that they begin puberty normally. Most women with Turner syndrome continue taking estrogen replacement therapy throughout their life, until the average age of menopause is reached.

Thyroid hormone replacement therapy may also be recommended to treat any potential thyroid disease; hypothyroidism is a common complication of Turner syndrome.

Most women with Turner syndrome are unable to conceive children naturally and will need in vitro fertilization (IVF) — in which a donor egg is used — if they wish to give birth. Because pregnancy with Turner syndrome can be risky, women are advised to consult members of their medical care team before starting the process.

Surgery for Turner Syndrome

There’s no surgical procedure designed to cure or treat Turner syndrome. However, because women with the condition are at increased risk for developing gonadal tumors — tumors made up of cells normally found in the testicles and ovaries — it’s recommended that nonfunctioning gonadal tissue be removed via surgery.

The Turner Syndrome Care Team

Evaluation and monitoring for health complications associated with Turner syndrome throughout life can help to treat these problems early, before they progress.

As a result, girls and women with the condition will likely see their care team change and evolve over time. However, in general, the care team should include these practitioners:

• Primary care doctor or pediatrician
• Geneticist
• Gynecologist
• Endocrinologist
• Cardiologist
• Orthopedist
• Ear, nose, and throat (ENT) specialist
• Audiologist (hearing specialist)
• Gastroenterologist
• Ophthalmologist (eye specialist)
• Mental health professional
• Fertility specialist

Prevention of Turner Syndrome

There’s no way to prevent Turner syndrome. It’s caused by a random genetic error that leads to a missing X chromosome in the father’s sperm or the mother’s egg. (8)

Parents can’t prevent the genetic error from happening.

Although most women with Turner syndrome can lead a normal life, with a close-to-average lifespan, the condition has been linked to an increased risk for a number of health complications, including: (1,7)

• Heart problems
• High blood pressure
• Hearing difficulties
• Vision problems
• Kidney problems
• Diabetes
• Underactive thyroid (hypothyroidism)
• Celiac disease
• Inflammatory bowel disease
• Skeletal health issues
• Mental health problems and learning difficulties
• Infertility and pregnancy complications

Many babies born with Turner syndrome have heart defects that increase their risk for a number of heart diseases, including congestive heart failure.

Similarly, later in life, women with Turner syndrome have an increased risk of high blood pressure, which also increases their risk for developing diseases of the heart and blood vessels.

Hearing loss is also common with Turner syndrome, due in some cases to the gradual loss of nerve function in the ears. Women with the condition are also at increased risk for frequent middle ear infections, which can also cause hearing loss.

Hearing aids can help offset any hearing loss and improve performance in learning and social environments.

Girls and women with Turner syndrome are also more likely to have weakness in the muscles that control eye movements (strabismus), nearsightedness, and other vision problems.

Kidney deformities in girls and women with Turner syndrome may increase their risk for high blood pressure and urinary tract infections.

Women with Turner syndrome are more likely to develop hypothyroidism caused by the autoimmune disorder Hashimoto's thyroiditis, as well as diabetes, celiac disease (gluten intolerance), and inflammatory bowel disease (IBD).

Problems with the growth and development of bones in girls and women with Turner syndrome increase their risk for scoliosis (abnormal curvature of the spine) and kyphosis (rounding of the upper back), while older women with the condition are more likely to develop osteoporosis (or weak, brittle bones), which may cause them to experience more bone fractures.

Although most girls and women with Turner syndrome are of normal intelligence, they may be at increased risk for learning disabilities, as well as difficulties with math, memory, and attention. They may also have problems functioning well in social situations, and they may be at increased risk for attention deficit hyperactivity disorder (ADHD).

Finally, most women with Turner syndrome are infertile, although they may become pregnant following assisted reproductive technology involving in vitro fertilization with a donor egg. However, women with Turner syndrome are also at increased risk for high blood pressure and aortic dissection during pregnancy.

Turner syndrome affects only those born female. Although it is the most common genetic disorder in females, it occurs in only approximately one in 2,500 newborn girls worldwide. (2)

However, it occurs often in pregnancies that don’t survive to term, including miscarriages and stillbirths.

It’s estimated that more than 70,000 women are living with Turner syndrome in the United States.

There are no known racial or ethnic differences that influence the frequency of Turner syndrome, but the prevalence of Turner syndrome in Black, Indigenous, and People of Color (BIPOC) communities has not been widely studied.

However, a survey of births in North Carolina over a five-year period found that the condition was most common in American Indian infants (5.1 in 10,000 live female births) and white infants (2.3 in 10,000 live female births), according to the March of Dimes. (9)

The same analysis found that 1.1 in 10,000 live female births among Black Americans in North Carolina between 2012 and 2016 had Turner syndrome.

Meanwhile, 1.8 in 10,000 live female births among Hispanic Americans in North Carolina between 2012 and 2016 had Turner syndrome.

A variety of chromosomal abnormalities can occur when the egg or the sperm is formed or during the early developmental stages of the fetus.

In some cases, the abnormality causes the baby to have an extra chromosome — or three of a given chromosome rather than the usual two. Down syndrome is an example of a disorder in which most people who have it have three copies of chromosome 21 instead of two.

In other cases, the abnormality involves a section of a chromosome being either deleted or duplicated. (10)

Many chromosomal abnormalities result in birth defects and developmental delays. They are also a major cause of miscarriages and stillbirths. (11)

But many individuals born with chromosomal abnormalities also go on to live normal, happy, and productive lives.

If your child is born with a genetic or chromosomal disorder, ask your healthcare provider what treatments and other services are available to you and your child. For some children, various types of therapies, such as physical therapy and speech therapy, and special educational programs can assist in their growth and development. And for parents and other family members, joining a support group for similarly affected families can be invaluable.

Turner Syndrome Society of the United States

The TSSUS educates and builds community among girls and women with Turner syndrome through webinars, Zoom meetings, and volunteer-led local Resource Groups. It also has a link to the Turner Syndrome Research Registry.

Turner Syndrome Clinic at Massachusetts General Hospital

MassGeneral offers basic information about Turner syndrome and its common complications, as well as advice on driving safely when you have Turner syndrome.

Turner Syndrome Foundation

The Turner Syndrome Foundation is an advocacy organization that supports research into Turner syndrome and offers support for those who have it via the Star Sisters program.

Turner Syndrome Global Alliance

The TSGA was founded by parents of girls with Turner syndrome to increase resources available to adults with Turner syndrome and to raise interest in and funds for research on the condition.

The Magic Foundation

The Magic Foundation provides support services to families of children with a variety of conditions that affect their growth, including Turner syndrome.

Additional reporting by Brian P. Dunleavy.