Turner syndrome

Overview

Turner syndrome, a condition that affects only females, results when one of the X chromosomes (sex chromosomes) is missing or partially missing. Turner syndrome can cause a variety of medical and developmental problems, including short height, failure of the ovaries to develop and heart defects.

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

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 healthy, independent lives.

Symptoms

Signs and symptoms of Turner syndrome may vary among girls and women with the disorder. For some girls, the presence of Turner syndrome may not be readily apparent, but in other girls, several physical features are apparent early. Signs and symptoms can be subtle, developing slowly over time, or significant, such as heart defects.

Before birth

Turner syndrome may be suspected prenatally based on prenatal cell-free DNA screening — a method to screen for certain chromosomal abnormalities in a developing baby using a blood sample from the mother — or prenatal ultrasound. Prenatal ultrasound of a baby with Turner syndrome may show:

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

At birth or during infancy

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

• Wide or weblike neck
• Low-set ears
• Broad chest with widely spaced nipples
• High, narrow roof of the mouth (palate)
• 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
• Slowed growth
• Cardiac defects
• Low hairline at the back of the head
• Receding or small lower jaw
• Short fingers and toes

In childhood, teens and adulthood

The most common signs in almost all girls, teenagers and young women with Turner syndrome are short stature and ovarian insufficiency due to ovarian failure. Failure of the ovaries to develop may occur at birth or gradually during childhood, the teen years or young adulthood. Signs and symptoms of these include:

• Slowed growth
• No growth spurts at expected times in childhood
• Adult height significantly less than might be expected for a female member of the family
• Failure to begin sexual changes expected during puberty
• Sexual development that "stalls" during teenage years
• Early end to menstrual cycles not due to pregnancy
• For most females 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. It's important to get a prompt, accurate diagnosis and appropriate care. See your doctor if there are concerns about the possibility of Turner syndrome. Your doctor may refer you to a physician who specializes in genetics (geneticist) or in hormone disorders (endocrinologist) for further evaluation.

Causes

Most people are born with two sex chromosomes. Males inherit the X chromosome from their mothers and the Y chromosome from their fathers. Females inherit one X chromosome from each parent. In females who have Turner syndrome, one copy of the X chromosome is missing, partially missing or changed.

The genetic changes 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.
• X chromosome changes. Changed or missing parts of one of the X chromosomes can occur. Cells have one complete and one altered copy. This error can occur in the sperm or egg with all cells having one complete and one altered copy. Or the error can occur in cell division in early fetal development so that only some cells contain the changed or missing parts of one of the X chromosomes (mosaicism).
• 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 female, but the presence of Y chromosome material increases the risk of developing a type of cancer called gonadoblastoma.

Effects of the missing or changed chromosome

The missing or changed X chromosome of Turner syndrome causes problems during fetal development and other developmental problems after birth — for example, short stature, ovarian insufficiency and heart defects. Physical characteristics and health complications that arise from these chromosomal issues vary greatly.

Risk factors

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.

Complications

Turner syndrome can affect the proper development of several body systems, but this varies greatly among individuals with the syndrome. Complications that can occur include:

• Heart problems. Many infants with Turner syndrome are born with heart defects or even slight abnormalities in heart structure that increase their risk of serious complications. Heart defects often include problems with the aorta, the large blood vessel that branches off the heart and delivers oxygen-rich blood to the body.
• High blood pressure. Turner syndrome can increase the risk of high blood pressure — a condition that increases the risk of developing diseases of the heart and blood vessels.
• Hearing loss. Hearing loss is common with Turner syndrome. In some cases, this is due to the gradual loss of nerve function. An increased risk of frequent middle ear infections can also result in hearing loss.
• Vision problems. An increased risk of weak muscle control of eye movements (strabismus), nearsightedness and other vision problems can occur with Turner syndrome.
• Kidney problems. Turner syndrome may be associated with malformations of the kidneys. Although these abnormalities generally don't cause medical problems, they may increase the risk of urinary tract infections.
• Autoimmune disorders. Turner syndrome can increase the risk of an underactive thyroid (hypothyroidism) due to the autoimmune disorder Hashimoto's thyroiditis. There is also an increased risk of diabetes. Sometimes Turner syndrome is associated with gluten intolerance (celiac disease) or inflammatory bowel disease.
• 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). Turner syndrome can also increase the risk of developing weak, brittle bones (osteoporosis).
• Learning disabilities. Girls and women with Turner syndrome usually have normal intelligence. However, there is increased risk of learning disabilities, particularly with learning that involves spatial concepts, math, memory and attention.
• Mental health issues. Girls and women with Turner syndrome may have challenges functioning in social situations, may experience anxiety and depression, and may have an increased risk of attention-deficit/hyperactivity disorder (ADHD).
• Infertility. Most females with Turner syndrome are infertile. However, a very small number may become pregnant spontaneously, and some can become pregnant with fertility treatment.
• Pregnancy complications. Because women with Turner syndrome are at increased risk of complications during pregnancy, such as high blood pressure and aortic dissection, they should be evaluated by a heart specialist (cardiologist) and a high-risk pregnancy doctor (maternal-fetal medicine specialist) before pregnancy.

Diagnosis

If, based on signs and symptoms, the doctor suspects that your child has Turner syndrome, a lab test will be done to analyze your child's chromosomes. The test involves a blood sample. Occasionally, your doctor may also request a cheek scraping (buccal smear) or skin sample. The chromosome analysis determines whether or not there is a missing X chromosome or a change in one of the X chromosomes.

Prenatal diagnosis

A diagnosis is sometimes made during fetal development. Certain features on an ultrasound image may raise suspicion that your baby has Turner syndrome or another genetic condition affecting development in the womb.

Prenatal screening tests that evaluate the baby's DNA in the mother's blood (prenatal cell-free fetal DNA screening or noninvasive prenatal screening) may also indicate an increased risk of Turner syndrome. However, doing a karyotype during pregnancy or after delivery is recommended to confirm the diagnosis.

If Turner syndrome is suspected before birth (prenatally), your pregnancy and childbirth specialist (obstetrician) may ask if you're interested in additional tests to make a diagnosis before your baby is born. One of two procedures can be performed to test prenatally for Turner syndrome:

• Chorionic villus sampling. This involves taking a small piece of tissue from the developing placenta. The placenta contains the same genetic material as the baby. The chorionic villus cells can be sent to the genetics lab for chromosome studies. This is usually done between 11 and 14 weeks of pregnancy.
• Amniocentesis. In this test, a sample of the amniotic fluid is taken from the uterus. The baby sheds cells into the amniotic fluid. The fluid can be sent to the genetics lab for study of the baby's chromosomes in these cells. This is typically done after 14 weeks of pregnancy.

Discuss the benefits and risks of prenatal testing with your doctor.

Treatment

Because symptoms and complications vary, treatments are tailored to address the individual's specific problems. Evaluation and monitoring for medical or mental health issues associated with Turner syndrome throughout life can help to address problems early.

The primary treatments for nearly all girls and women with Turner syndrome include hormone therapies:

• Growth hormone. Growth hormone therapy — usually given daily as an injection of recombinant human growth hormone — is typically recommended to increase height as much as possible at appropriate times during early childhood until the early teen years. Starting treatment early can improve height and bone growth.
• Estrogen therapy. Most girls with Turner syndrome need to start estrogen and related hormone therapy in order to begin puberty. Often, estrogen therapy is started around age 11 or 12 years. Estrogen helps to promote breast development and improve the size (volume) of the uterus. Estrogen helps with bone mineralization, and when used with growth hormone, may also help with height. Estrogen replacement therapy usually continues throughout life, until the average age of menopause is reached.

Other treatments are tailored to address particular problems as needed. Regular checkups have shown substantial improvements in the health and quality of life for girls and women with Turner syndrome.

It's important to help your child prepare for the transition from care with your pediatrician to adult medical and mental health care. A primary care doctor can help to continue coordination of care among a number of specialists throughout life.

Health care team

Because Turner syndrome can result in developmental concerns and medical complications, several specialists may be involved in screening for specific conditions, making diagnoses, recommending treatments and providing care.

Teams may evolve as needs change throughout life. Care team specialists may include some or all of these professionals, and others as needed:

• Hormone disorder specialist (endocrinologist)
• Specialist in women's health (gynecologist)
• Physician who specializes in genetics (medical geneticist)
• Heart specialist (cardiologist)
• Specialist in skeletal disorders (orthopedist)
• Specialist in urinary tract disorders (urologist)
• Ear, nose and throat (ENT) specialist
• Specialist in gastrointestinal disorders (gastroenterologist)
• Specialist in vision problems and other eye disorders (ophthalmologist)
• Specialist in hearing problems (audiologist)
• Mental health professional, such as a psychologist or psychiatrist
• Developmental therapist, who specializes in therapy to help your child develop age-appropriate behaviors, social skills and interpersonal skills
• Special education instructors
• Fertility specialist (reproductive endocrinologist)

Pregnancy and fertility treatment

Only a small percentage of women with Turner syndrome can become pregnant without fertility treatment. Those who can are still likely to experience failure of the ovaries and subsequent infertility very early in adulthood. So it's important to discuss reproductive goals with your health care provider.

Some women with Turner syndrome can become pregnant with the donation of an egg or embryo. A reproductive endocrinologist can discuss options and help evaluate the chances of success.

In most cases, females with Turner syndrome have high-risk pregnancies. It's important to discuss those risks before pregnancy with a high-risk obstetrician — a specialist in maternal-fetal medicine who focuses on high-risk pregnancies — or a reproductive endocrinologist.

Coping and support

The Turner Syndrome Society of the United States and other organizations provide educational materials, resources for families and information about support groups. Groups for parents provide an opportunity to exchange ideas, develop coping strategies and locate resources.

Peer groups for girls with Turner syndrome can help reinforce self-esteem and provide a social network of people who understand how to live with Turner syndrome.

Preparing for your appointment

How you learn your child has Turner syndrome may vary.

• Before birth. Turner syndrome may be suspected from prenatal cell-free DNA screening or certain features may be detected on prenatal ultrasound screening. Prenatal diagnostic testing can confirm the diagnosis.
• At birth. If certain conditions — such as a webbed neck or other distinct physical features — are readily apparent at birth, diagnostic tests will likely begin before your child leaves the hospital.
• During childhood or teen years. Your family doctor or pediatrician may suspect the disorder later if growth isn't occurring at an expected rate or puberty doesn't begin at an expected time. Diagnostic testing can confirm the diagnosis.

Well-baby visits and annual checkups

It's important to take your child to all regularly scheduled well-baby visits and annual appointments throughout childhood. These visits are an opportunity for the doctor to take height measurements, note delays in expected growth and identify other problems in physical development.

The doctor may ask questions such as:

• What concerns do you have about your child's growth or development?
• How well does your child eat?
• Has your child begun to show signs of puberty?
• Is your child experiencing any learning difficulties at school?
• How does your child do in peer-to-peer interactions or social situations?

Talking to the doctor about Turner syndrome

If your family doctor or pediatrician believes that your child shows signs or symptoms of Turner syndrome and suggests diagnostic tests, you may want to ask these questions:

• What diagnostic tests are needed?
• When will we know the results of the tests?
• What specialists will we need to see?
• How will you screen for disorders or complications that are commonly associated with Turner syndrome?
• How can I help monitor my child's health and development?
• Can you suggest educational materials and local support services regarding Turner syndrome?