Turner Syndrome (Monosomy X) in Children
What is Turner syndrome (TS) 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.
What causes TS in a child?
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 missing.
What are the symptoms of TS in a child?
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 neck)
A low hairline at the back of the neck
Feeding problems as a baby
Small differences in the shape and position of the ears
Broad chest with widely spaced nipples
More small brown moles (nevi) on the skin than normal
Narrow top of the inside of the mouth
Eye problems requiring glasses
How is TS diagnosed in a child?
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 very accurate.
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
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 missing.
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.
How is TS treated in a child?
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.
What are possible complications of TS in a child?
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 development.
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 disabilities.
Other possible problems include:
Middle ear infections
High blood pressure
Low bone density and increased risk of fractures
Curving of the spine (scoliosis and kyphosis)
Inflammatory bowel disease
Vitamin D deficiency
Coronary heart disease as an adult
What can I do to prevent TS in my child?
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.
How can I help my child live with TS?
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 healthcare provider.
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 plan.
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 should I call my child’s healthcare provider?
Call the healthcare provider if your child has:
Key points about TS in children
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
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.