Pediatric Turner Syndrome

Turner syndrome (TS) is a genetic disorder that occurs in individuals born with female external genitalia. It causes many traits and problems. Children with TS are shorter. Many of them 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 child to child. Many of the health problems affecting children 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 female 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.

Turner syndrome occurs when a female child is missing an entire X-chromosome or has a defect in one of the X-chromosomes. About half of all children with Turner syndrome have a monosomy X disorder. Monosomy means that a person is missing one chromosome in the pair of X-chromosomes. Instead of 46 chromosomes, the person has only 45 chromosomes. This means a female child 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.

Other children with TS may have a structural defect in the X-chromosome with ‘missing’ and sometimes ‘extra’ pieces of the X-chromosome. A small number of these children may even have a piece of the Y-chromosome. Children with 'mosaic TS' have chromosome changes in only some cells, but not all cells. The features of TS depend on which part of the X chromosome is missing and how many cells are affected. So, there is a lot of variability in how children with Turner syndrome present.

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.

During a pregnancy, your 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.

Children with TS often have:

• Puffy hands and feet at birth
• Wide neck with folds of skin down the sides of neck (webbed neck)
• Short height
• 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
• Deep-set nails 
• Small jaw
• Narrow top of the inside of the mouth
• 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. These tests are very accurate.

Testing 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, which is not completely accurate and will need additional tests to confirm the diagnosis.

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 your healthcare provider thinks that your newborn baby 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-chromosome is missing or for defects in the X-chromosome.

Your 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 child with TS doesn’t have any problems as a baby or child. But healthcare providers may suspect TS if short stature or delay in puberty is noticed.

There is no cure for TS. But many of the more serious problems can be treated. For example, growth hormone can increase the final adult height. Hormone therapy can help to develop breasts and menstrual cycles. Surgery can fix coarctation of the aorta, and other heart defects if needed. Medicines are available to treat high blood pressure, diabetes and thyroid problems. Only a small number of women with TS are able to have children on their own, and pregnancy has risks in TS. But several others may be able to receive treatments to help preserve their eggs, if any, or have children with donor eggs.

Being shorter than normal is the most common feature of TS. The average adult height of a woman with TS is 4 feet, 8 inches. They may also have cubitus valgus. This means that when they stand with their arms at the side, the elbows will be slightly bent. Most children with TS will benefit from treatment with growth hormone over time.

Many women with TS are born with poorly formed ovaries or ovaries that do not work. Ovaries make estrogen. Without it the normal signs of puberty including breast development and menstrual periods don’t happen unless the child is given hormone therapy. Many children with the syndrome won’t be able to get pregnant on their own (are infertile) as adults. However, they may still be able to get pregnant with medical help. Most children 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. Nearly half of all children with TS are born with heart valve or blood vessel defects and about one in 10 children 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.

Children with TS generally have normal intelligence but are at higher risk of having attention, memory problems and learning disabilities and may have problems with spatial perception. They may also have increased anxiety and difficulty with social cognition.

Other possible problems include:

• Middle ear infections
• Diabetes
• Dry skin
• High blood pressure
• Low bone density and increased risk of fractures
• Curving of the spine (scoliosis and kyphosis)
• Hearing loss
• Hypothyroidism
• Celiac disease
• Inflammatory bowel disease
• Vitamin D deficiency
• Metabolic syndrome
• Coronary heart disease as an adult

If your baby 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 child with TS can also be helpful.
• If your child has any of the complications listed above, they will need screening and monitoring at periodic intervals. Make sure you understand the monitoring schedule that applies to your child.

Call the healthcare provider if your child has:

• Symptoms that don’t get better, or get worse
• New symptoms