What is Turner syndrome?
Turner syndrome occurs exclusively in females and is a chromosomal disorder that affects the sex chromosomes. Humans have 23 pairs of chromosomes, including one pair of sex chromosomes. Children inherit one set of chromosomes from each parent. For the sex chromosomes, girls inherit an X chromosome from each parent. Boys inherit a Y chromosome from their fathers and an X chromosome from their mothers. In Turner syndrome, one X chromosome is missing, partially missing, or changed in some way. This disrupts sex hormone production and causes other problems.
Turner syndrome is not hereditary. The chromosomal changes happen randomly. In most cases, there is an abnormality with the X chromosome in either the mother’s egg or the father’s sperm. Other times, the problem occurs as an error in early fetal development.
Turner syndrome is the most common sex chromosome abnormality in females. It occurs in about 1 in 2,500 live female births worldwide. It is even more common in pregnancies that result in miscarriage or stillbirth. The syndrome gets its name from the physician who described it in the 20th century. Other names for it include ovarian hypoplasia syndrome and 45,X or 45,X0.
Typically, Turner syndrome characteristics are obvious at birth or they develop by age 5. However, the physical effects and health problems with the condition can vary greatly. Girls with the condition usually have a wide or webbed neck, a low hairline on the neck, low ears, and a wide chest with widely spaced nipples. These girls may also have slow growth, short height, infertility, and heart problems. Complications from heart birth defects can become life-threatening.
Treating Turner syndrome often involves growth hormone and estrogen therapy. Girls with heart defects and other medical problems will need treatment for those conditions as well. While lifelong medical care is necessary, most girls and women with Turner syndrome can expect to live normal, healthy lives.
Make an appointment with your child’s doctor if you notice problems with growth (including puberty) or an unusual physical appearance.
What are the symptoms of Turner syndrome?
How Turner syndrome affects girls can vary quite a bit. It depends on the severity of the chromosomal abnormality. Some girls may have no noticeable signs of the condition. Others may have dramatic symptoms and health problems. Symptoms may also be apparent at birth or not develop until later in childhood or even adolescence.
Common symptoms of Turner syndrome
Having a short stature is the most common symptom of Turner syndrome. Most girls will also have slow growth, lack of growth spurts, and delayed puberty. This results in a final adult height that is below average, at around 4 feet, 8 inches. Other common physical characteristics include:
Arms that turn out at the elbows, swelling of the hands and feet, short fingers and toes, and narrow or upturned fingernails and toenails
Broad chest, widespread nipples, wide or webbed neck, and scoliosis of the spine
Ears that sit lower than usual, a low hairline on the neck, and more moles than usual
High or narrow palate, small or receding lower jaw, dental problems, and eye problems, including lazy eye and drooping eyelids
Lack of sexual development, including little or no breast development, no menstruation, and small ovaries that usually stop working very early
Turner syndrome can also affect several different body systems, resulting in various complications. While developmental delays and learning disabilities are possible, most girls with Turner syndrome have normal intelligence.
What causes Turner syndrome?
Turner syndrome is a chromosomal disorder that affects females. Normally, girls have two healthy X chromosomes. In Turner syndrome, there is only one healthy X chromosome. The other X chromosome is either completely or partially missing or it has a structural change. This results in low sex hormone levels and changes in development before and after birth.
In most cases, Turner syndrome is a sporadic disorder, meaning it occurs randomly. Rarely, a girl inherits an altered X chromosome from a parent.
The chromosomal alterations that cause Turner syndrome include:
Monosomy, which means one X chromosome is completely missing, affects about half of girls with Turner syndrome. It is the result of the mother’s egg or the father’s sperm randomly forming without an X chromosome. Every cell in a girl’s body will lack an X chromosome.
Mosaicism, which means some cells have two X chromosomes and some have only one copy. About 30% of cases are the result of this abnormality. It occurs randomly during development very early in pregnancy.
Partial deletion, which means part of one X chromosome is missing. This can occur randomly or be inherited from a parent in rare cases. Features of Turner syndrome may or may not be present.
There is also a form of mosaicism where some cells have an X chromosome and some Y chromosome material. The small percentage of girls with this form have a high risk of developing a cancer called gonadoblastoma.
What are the risk factors for Turner syndrome?
Turner syndrome occurs randomly. It is not hereditary in most cases.
Reducing your risk of Turner syndrome
Because it is a random occurrence, it is not possible to prevent Turner syndrome or reduce the risk to future children. Having one child with the condition does not increase the risk to other children. And the risk of Turner syndrome does not increase with the age of the mother.
How do doctors diagnose Turner syndrome?
To diagnose Turner syndrome, your child’s doctor will look for features of the disorder. If there is a high suspicion, a blood test (karyotype) can find missing chromosomes and chromosome abnormalities.
Prenatal testing can detect Turner syndrome in some cases. Certain features may be visible during a prenatal ultrasound. This includes heart problems and excess fluid around the baby’s neck. Amniocentesis and chorionic villus sampling can confirm Turner syndrome by looking for abnormal chromosomes.
What are the treatments for Turner syndrome?
There is no cure for Turner syndrome, but treatments can help manage the disorder. Treatment goals will vary from person to person because the features and complications vary. The main treatment options include:
Growth hormone: Most girls with Turner syndrome will need daily growth hormone injections. Starting treatment in childhood can increase height and bone growth. It is possible to achieve a final adult height in the normal range with early treatment. Treatment typically continues through the early teenage years.
Hormone replacement therapy: Giving estrogen around age 11 can help girls begin puberty, breast development, uterine growth, and menstruation. Estrogen also helps with bone, brain, heart and liver health. Cyclic progestins may also be necessary for normal menstruation. Hormone replacement usually continues until a woman reaches menopausal age.
Girls born with heart defects may require surgery to correct them.
Most girls will also be infertile because their ovaries stop working very early. Ovarian tissue often deteriorates before birth. However, the vagina and uterus are usually normal, especially with hormone replacement therapy. This means some women with Turner syndrome may be able to become pregnant with fertility treatments and donor eggs. Women with Turner syndrome are at increased risk of pregnancy complications.
What are the potential complications of Turner syndrome?
Turner syndrome can affect several body systems and the effects can vary widely. Possible complications include:
Hearing loss due to frequent infections and loss of nerve function
Heart problems, including birth defects of the aorta and aortic valve
Kidney problems, which can lead to high blood pressure
Learning disabilities and mental health problems
- Vision problems
Lifelong medical care from a variety of healthcare providers is usually necessary for girls and women with Turner syndrome.
Does Turner syndrome shorten life expectancy?
In general, Turner syndrome survival rate is high and women with the disorder can expect to live a fairly normal, healthy life. For some women, life expectancy is slightly shorter than normal. Effectively managing chronic medical conditions, such as diabetes and high blood pressure, can help extend survival.