Turner syndrome

Turner syndrome, a condition that affects only girls and women, results when a sex chromosome (the X chromosome) is missing or partially missing. Turner syndrome can cause a variety of medical and developmental problems, including short height, failure to start puberty, infertility, heart defects, certain learning disabilities and social adjustment problems.

Turner syndrome may be diagnosed before birth (prenatal), during infancy or in early childhood. Occasionally the diagnosis is delayed until the teen or young adult years in those who have mild signs and symptoms of Turner syndrome.

Nearly all girls and women with Turner syndrome need ongoing medical care from a variety of specialists. Regular checkups and appropriate care can help most girls and women lead relatively healthy, independent lives.

Symptoms Causes Risk factors Complications

Signs and symptoms of Turner syndrome may vary significantly.

Before birth

Prenatal ultrasound of a baby with Turner syndrome may show:

  • Large fluid collection on the back of the neck or other abnormal fluid collections
  • Heart abnormalities
  • Abnormal kidneys

At birth or during infancy

In some girls, a number of physical features and poor growth are apparent early. Signs of Turner syndrome at birth or during infancy may include:

  • Wide or weblike neck
  • Receding or small lower jaw
  • High, narrow roof of the mouth (palate)
  • Low-set ears
  • Low hairline at the back of the head
  • Broad chest with widely spaced nipples
  • Short fingers and toes
  • Arms that turn outward at the elbows
  • Fingernails and toenails that are narrow and turned upward
  • Swelling of the hands and feet, especially at birth
  • Slightly smaller than average height at birth
  • Delayed growth

In older girls, teens and young women

For some girls, the presence of Turner syndrome may not be readily apparent. Signs and symptoms in older girls, teenagers and young women that may indicate Turner syndrome include:

  • No growth spurts at expected times in childhood
  • Short stature, with an adult height of about 8 inches (20 centimeters) less than might be expected for a female member of her family
  • Learning disabilities, particularly with learning that involves spatial concepts or math, though intelligence is usually normal
  • Difficulty in social situations, such as problems understanding other people's emotions or reactions
  • Failure to begin sexual changes expected during puberty — due to ovarian failure that may have occurred by birth or gradually during childhood, adolescence or young adulthood
  • Sexual development that "stalls" during teenage years
  • Early end to menstrual cycles not due to pregnancy
  • For most women with Turner syndrome, inability to conceive a child without fertility treatment

When to see a doctor

Sometimes it's difficult to distinguish the signs and symptoms of Turner syndrome from other disorders. So it's important to get a prompt, accurate diagnosis and appropriate care. See your doctor if you believe your daughter shows signs of Turner syndrome or if you have concerns about her physical, sexual or behavioral development.

Most people are born with two sex chromosomes. A boy inherits the X chromosome from his mother and the Y chromosome from his father. A girl inherits one X chromosome from each parent. If a girl has Turner syndrome, one copy of the X chromosome is missing or significantly changed.

The genetic alterations of Turner syndrome may be one of the following:

  • Monosomy. The complete absence of an X chromosome generally occurs because of an error in the father's sperm or in the mother's egg. This results in every cell in the body having only one X chromosome.
  • Mosaicism. In some cases, an error occurs in cell division during early stages of fetal development. This results in some cells in the body having two complete copies of the X chromosome. Other cells have only one copy of the X chromosome, or they have one complete and one altered copy.
  • Y chromosome material. In a small percentage of Turner syndrome cases, some cells have one copy of the X chromosome and other cells have one copy of the X chromosome and some Y chromosome material. These individuals develop biologically as girls, but the presence of Y chromosome material increases the risk of developing a type of cancer called gonadoblastoma.

Effect of the chromosomal errors

The missing or altered X chromosome of Turner syndrome causes errors during fetal development and other developmental problems after birth — short stature, ovarian failure and learning disabilities. Physical characteristics and health complications that arise from the chromosomal error vary greatly.

The loss or alteration of the X chromosome occurs randomly. Sometimes, it's because of a problem with the sperm or the egg, and other times, the loss or alteration of the X chromosome happens early in fetal development.

Family history doesn't seem to be a risk factor, so it's unlikely that parents of one child with Turner syndrome will have another child with the disorder.

Turner syndrome can affect the proper development of several body systems. A number of complications may occur, including:

  • Heart problems. Many girls and women with Turner syndrome were born with heart defects or even slight abnormalities in heart structure that increase their risk of serious complications. Defects in the main blood vessel leading out of the heart (aorta) increase the risk of a tear in the inner layer of the aorta (aortic dissection). A defect in the valve between the heart and the aorta may also increase the risk of a narrowing of the valve (aortic valve stenosis).
  • Risk factors for cardiovascular disease. Women with Turner syndrome have an increased risk of diabetes and high blood pressure — conditions that increase the risk of developing diseases of the heart and blood vessels.
  • Hearing loss. Hearing loss is common among girls or women with Turner syndrome. In some cases, this is due to the gradual loss of nerve function. Also, slight abnormalities in the shape of the skull increase the risk of frequent middle ear infections and hearing loss related to these infections.
  • Kidney problems. About one-third of girls with Turner syndrome have some malformation of the kidneys. Although these abnormalities generally don't cause medical problems, they may increase the risk of high blood pressure and urinary tract infections.
  • Immune disorders. Girls and women with Turner syndrome have an increased risk of certain immune system disorders, including a condition that causes an underactive thyroid (hypothyroidism). This disorder results in the low production of hormones important for controlling heart rate, growth and metabolism. There's also an increased risk of diabetes, inflammatory bowel disease, and wheat intolerance (celiac disease), a condition that affects how your body processes carbohydrates in food.
  • Dental problems. Poor or abnormal tooth development may lead to a greater risk of tooth loss. The shape of the roof of the mouth and lower jaw often results in crowded teeth and a poorly aligned bite.
  • Vision problems. Girls with Turner syndrome have an increased risk of weak muscle control of eye movements (strabismus) and farsightedness (hyperopia).
  • Skeletal problems. Problems with the growth and development of bones increase the risk of abnormal curvature of the spine (scoliosis) and forward rounding of the upper back (kyphosis). Women with Turner syndrome are also at increased risk of developing weak, brittle bones (osteoporosis).
  • Pregnancy complications. Most women with Turner syndrome are infertile. However, a very small number of women may become pregnant spontaneously, and some can become pregnant with fertility treatment. Because women with Turner syndrome are at increased risk of aortic dissection during pregnancy, they should be evaluated by a cardiologist before pregnancy. They're also at risk of developing high blood pressure and gestational diabetes during pregnancy.
  • Psychological issues. Girls and women with Turner syndrome may have learning disabilities, particularly math and spatial concepts, difficulties functioning well in social situations, and an increased risk of attention-deficit/hyperactivity disorder (ADHD).
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