Turner syndrome (TS)

What is Turner syndrome?

Turner syndrome is a rare female-only genetic disorder, only affecting 1–2 in every 4,000 women. Women with Turner syndrome have one normal X chromosome and either a completely missing or partially missing second X chromosome.

Turner syndrome is associated with certain symptoms and physical characteristics, but they can vary widely from woman to woman. Almost all women with Turner syndrome are shorter than average and have underdeveloped ovaries. Girls with Turner syndrome are therefore unlikely to start their monthly periods and undergo the other changes associated with puberty.

There’s unfortunately no cure. However, with regular medical monitoring to detect and prevent potential complications, women with Turner syndrome can lead relatively normal and healthy lives.

Hear from a parent of a daughter living with Turner syndrome and how they got their diagnosis. https://morethanheight.com/en/life-with-growth-disorders/living-with-turner-syndrome/

What causes Turner syndrome?

Turner syndrome is the result of a chromosomal abnormality, which happens entirely by chance.

Chromosomes store our genetic information, most people are born with 46 chromosomes, the 23rd pair of chromosomes, X and Y determine your sex. If you are assigned female at birth, you will have a pair of X chromosomes (46,XX) whereas if you are assigned male at birth, you will have one X and one Y chromosome( 46,XY).

However, if you have Turner syndrome one of your X chromosomes is either completely or partially missing.

The chromosomal abnormality is the result of a random error in cell division. This could occur when either the sperm and the egg are being formed, or after the sperm and the egg have fused to form the embryo.

Unlike other chromosomic disorders, advanced maternal age is not linked to an increased likelihood of having a child with Turner syndrome. There is no known cause or way of preventing it.

What is mosaic Turner syndrome?

Around 55% of cases of Turner syndrome are mosaic Turner syndrome, making it the most common form. Women with mosaic Turner syndrome often have fewer, milder symptoms. They are also more likely to go through puberty naturally and to be able to conceive naturally than those with classic Turner syndrome.

For most people, all of our cells have the same chromosomal arrangement and there is no variation. However, some people have two or more genetically different sets of cells in their body, which is called mosaicism.

In mosaic Turner syndrome not all cells have the same chromosomal arrangement. Some cells may have one normal X chromosome and one partially missing. Some cells may have one normal X chromosome and one completely missing. Some cells may have two normal X chromosomes. Some cells may have one X chromosome and one Y chromosome.

What are the symptoms of Turner syndrome?

Turner syndrome is characterised by a wide range of symptoms. Not everyone with Turner syndrome will have all these symptoms and they can appear at different ages. However, almost all women with Turner syndrome have underdeveloped ovaries and shorter than average height.

Other typical characteristics of Turner syndrome are:

• Swollen hands or feet (mainly in babies)
• Low hairline
• Webbed neck (a fold of skin that runs along the neck’s side, down to the shoulders. It also usually includes extra skin, with hair that extends below the back hairline)
• Cubitus valgus (when fully extended, the forearm extends at an angle further from the body than normal)
• Low-set ears
• Droopy eyelids
• Broad chest and widely spaced nipples
• Short fingers
• Short fourth toe
• Narrow and convex nails

90–95% of women with Turner syndrome have underdeveloped ovaries. During puberty, the ovaries produce sex hormones that result in sexual development and periods. If untreated, most girls with Turner syndrome are unlikely to go through the changes associated with puberty and start monthly periods. Consequently, most women with Turner syndrome are unable to become pregnant naturally and are considered infertile.

Girls with Turner syndrome will commonly grow at a slower rate than girls without Turner syndrome. It is most obvious when they reach puberty, when they do not go through the normal growth spurt others their age experience.

If your child is short in stature, keeping track of their growth can help identify if there is a problem early on. Compare your child’s measurements to the national average to see if they are within a healthy range.

What are the complications associated with Turner syndrome?

There are also certain medical issues associated with Turner syndrome, including:

• Scoliosis
• Type 1 and type 2 diabetes
• Structural heart defects
• Heart disease
• Hashimoto’s thyroiditis
• Hearing problems
• High blood pressure
• Chronic ear infections
• Osteoporosis (weak bones)
• Short sightedness
• Obesity
• Inflammatory bowel disease (IBD)
• Structural kidney defects
• Learning difficulties

How is Turner syndrome diagnosed?

Women with Turner syndrome vary in terms of which symptoms they have and how severe they are. Currently, only 15–30% of people with Turner syndrome are diagnosed in the first year of life.

Girls with Turner syndrome are often identified when they fall behind on growth compared to others their age. On average, Turner syndrome is diagnosed at the age of 15, when signs of delayed growth and sexual development become apparent.

If your daughter has one or more symptoms listed above, it’s important you speak to a doctor. The only way to confirm a diagnosis of Turner syndrome is through a process called karyotyping. Karyotyping involves looking at all the chromosomes in detail by analysing a sample of blood.

If karyotyping identifies that your daughter has Turner syndrome, they may order additional tests to check early on for any of the medical issues associated with Turner syndrome. This may include additional blood tests, hearing tests and tests looking at your daughter’s heart and kidneys.

It is important you speak to your doctor if you have any concerns about your child’s height. Use this helpful guide on what questions to ask, and what to expect from your visit. https://morethanheight.com/en/talk-to-your-doctor/visiting-your-paediatrician/