Turner Syndrome (Monosomy X) in Children
Turner syndrome (TS or monosomy X)
is a genetic disorder that occurs in girls. It causes many traits and problems. Girls
with TS are shorter than most girls. They don’t go through normal puberty as they grow
into adulthood. They may also have other health problems such as heart or kidney
problems. The seriousness of these problems varies from girl to girl. Many of the health
problems affecting girls with Turner syndrome can be managed or fixed with treatment.
Turner syndrome is rare. It occurs in about 1 in 2,000 to 2,500 girl babies.
When a baby is conceived, a normal egg cell and normal sperm cell start with 46 chromosomes. The egg and sperm cells then divide in half. The egg and sperm cells then have 23 chromosomes each. When a sperm with 23 chromosomes fertilizes an egg with 23 chromosomes, the baby will then have a complete set of 46 chromosomes, or 23 pairs. Half are from the father and half are from the mother. The 23rd pair is called the sex chromosomes. In females, the 23rd pair is two X chromosomes. In males, the 23rd pair is one X and one Y chromosome.
There are 2 types of Turner
syndrome: monosomy X TS and mosaic TS. About half of all girls with Turner syndrome have
a monosomy disorder. Monosomy means that a person is missing one chromosome in the pair.
Instead of 46 chromosomes, the person has only 45 chromosomes. This means a girl with TS
has only one X chromosome in her 23rd pair.
Sometimes an error occurs when an egg or sperm cell is forming. This causes it to have a
missing sex chromosome. But it is often an error that happened by chance when the
father's sperm cell was forming. The missing sex chromosome error can occur in either
the mother's egg cell or the father's sperm cell.
Girls with mosaic TS have
chromosome changes in only some cells, but not all cells. A small number of cases have
the normal number of 46 chromosomes, but with part of the X chromosome missing. When
only part of an X chromosome is missing (deletion), a girl with the syndrome will often
have milder signs of TS. The features of TS depend on which part of the X chromosome is
During a pregnancy, the healthcare provider may have seen a structure called a cystic hygroma during a fetal ultrasound. A cystic hygroma is a fluid-filled sac at the base of the neck. It often goes away before birth. But sometimes the sac is there when the baby is born.
Girls with TS often have:
- Puffy hands and feet at birth
- Wide neck with folds of skin down the sides of neck (webbed
- Short height
- A low hairline at the back of the
- Feeding problems as a baby
- Small differences in the shape and
position of the ears
- Broad chest with widely spaced
- More small brown moles (nevi) on the
skin than normal
- Deep-set nails
- Small jaw
- Narrow top of the inside of the
- Skeletal problems
- Eye problems requiring glasses
Chromosome problems such as TS can
often be diagnosed before birth. This is done by looking at cells in the amniotic fluid
or from the placenta. This can also be done by looking at the amount of the baby’s DNA
in the mother's blood. This is called noninvasive prenatal screening. These tests are
Fetal ultrasound during pregnancy can also show the possibility of Turner syndrome. But ultrasound is not 100% accurate. Problems due to the disorder may not be seen with ultrasound.
If a healthcare provider thinks
that your newborn baby girl may have TS, he or she will often take a small sample of
your baby’s blood. The lab will look at the sample to see if one X sex chromosome is
The healthcare provider may refer you to a genetic counselor. This expert can explain the results of chromosome tests, as well as tests available to diagnose chromosome problems before a baby is born.
Sometimes a girl with TS doesn’t have any problems as a baby or child. It’s only when she doesn’t go through puberty or is shorter than her peers that her healthcare provider may suspect TS.
There is no cure for TS. But many of the more serious problems can be treated. For example, growth hormone and androgen therapy can increase the final adult height of a girl. She can also take hormone therapy to develop secondary sex traits such as breasts, pubic hair, and underarm hair. Surgery can fix coarctation of the aorta, if needed. And medicines are available to treat high blood pressure, diabetes, and thyroid problems. A woman with TS can have children by using donor eggs.
Being shorter than normal is the
most common feature of TS as a girl grows. The average adult height of a woman with TS
is 4 feet, 8 inches. A girl may also have cubitus valgus. This means that when she
stands with her arms at her side, her elbows will be slightly bent. She can’t keep her
arms perfectly straight at her side. Most girls with TS will need treatment with growth
hormone over time.
Most women with TS are born with
poorly formed or missing ovaries. Ovaries make estrogen. Without it, a girl with TS will
not develop sexually. The normal signs of puberty don’t happen unless the girl is given
hormone therapy. This includes breast development, menstrual periods, and growth of
pubic hair and hair elsewhere on the body. Most girls with the syndrome won’t be able to
have children (are infertile) as adults. Most girls will need to be treated with
estrogen at some point for a normal progression of puberty and sexual
Other common problems with TS affect the heart, kidney, and thyroid. About 1 in 10 girls with TS is born with coarctation of the aorta. This means the main artery that leaves the heart is narrowed. This problem sometimes needs to be fixed with surgery.
Girls with TS generally have normal
intelligence. They tend to score higher on their verbal IQ than their nonverbal IQ. But
they may have problems with spatial perception. They may also have certain learning
Other possible problems include:
- Middle ear infections
- Dry skin
- High blood pressure
- Low bone density and increased risk of fractures
- Curving of the spine (scoliosis and kyphosis)
- Hearing loss
- Celiac disease
- Inflammatory bowel disease
- Vitamin D deficiency
- Metabolic syndrome
- Coronary heart disease as an adult
Researchers don’t know how to
prevent the chromosome error that causes this disorder. In general, a woman who has a
child with Turner syndrome is not at increased risk of having another baby with the
condition. TS is often not inherited in families. It happens randomly.
If your baby girl is born with TS, there are things you can do to take care of yourself and your baby.
- Keep all appointments with your baby’s
- Talk with your healthcare provider
about other providers who will be part of your child’s care. Your child may receive
care from a multidisciplinary team that may include experts such as counselors,
social workers, genetic counselors, physical therapists, and speech therapists.
- Call your healthcare provider if you
are concerned about your baby’s symptoms.
- Think about having genetic testing and
counseling to understand your risk.
- Tell others about your baby’s
condition. Work with your child’s healthcare provider to create a treatment
- Reach out for support from local
community services. Being in touch with other parents who have a daughter with TS can
also be helpful.
- If your child has any of the complications listed above, she
will need screening and monitoring at periodic intervals. Make sure you understand
the monitoring schedule that applies to your child.
When to Call a Healthcare Provider
Call the healthcare provider if your child has:
- Symptoms that don’t get better, or get worse
- New symptoms
- Turner syndrome (TS) is a genetic disorder that occurs in girls.
- Girls with TS generally have normal intelligence. But they are shorter than most girls. They don’t go through normal puberty as they grow into adulthood. And they may also have heart, thyroid, or kidney problems.
- There is no cure for TS. But many of the more serious problems can be treated with hormone therapy, surgery, and medicines.
- A woman with TS can have children by using donor eggs.
- Chromosome problems such as TS can
often be diagnosed before birth. This is done by looking at cells in the amniotic
fluid or from the placenta. These tests are very accurate.
- Experts don’t know how to prevent the
chromosome error that causes TS. It often happens by chance during conception. It
does not often run in families.
Tips to help you get the most from a visit to your child’s healthcare provider:
- Know the reason for the visit and what you want to happen.
- Before your visit, write down questions you want answered.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.
- Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
- Ask if your child’s condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if your child does not take the medicine or have the test or procedure.
- If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
- Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.