A chromosomal disorder in which a female is born with only one “X” chromosome. This syndrome is very rare (fewer than 1 million cases per year in India). In this case treatment can help, but this condition can’t be cured.
Turner syndrome results from a missing or incomplete sex chromosome.
Turner syndrome is named after Henry Turner, Turner was an endocrinologist from Illinois, who described about this syndrome in 1983. In Europe, it is often called Ullrich-Turner syndrome or even Bonn Evie-Ullrich-Turner syndrome. Earlier cases had also been described by European doctors.
The first published report of a female with a 45, X karyotype was in 1959 by Doctor Charles Ford and colleagues in Harwell, Oxfordshire, and Guy’s Hospital in London. It was found in a 14 year old girl with symptoms of Turner syndrome.
Sign & Symptoms
The following common symptoms of Turner syndrome, an individual may have and any combination of symptoms and is unlikely to have all these symptoms.
- Short stature
- Broad chest
- Low posterior hairline
- Low –set ears
- Reproductive sterility
- Increased weight, obesity
- Shortened metacarpal IV
- Small fingernails
- Characteristic facial features
- Webbed neck
- Aortic valve stenosis
- Coarctation of the aorta
- Bicuspid aortic valve (most common cardiac problem)
- Horseshoe kidney
- Visual impairments – sclera, cornea, glaucoma, etc.
- Ear infections and hearing loss
- High waist-to-hip ratio (the hips are not much bigger than the waist)
- Attention deficit hyperactivity disorder (problems with concentration, memory, attention with hyperactivity seen mostly in childhood and adolescence)
- Nonverbal learning disability (problems with maths, social skills, and spatial relations)
Other features may include a small lower jaw, cubitus valgus, etc.
Turner syndrome is related to the X chromosome, which is one of the two sex chromosomes. People typically have two sex chromosomes in each cell: females have two X chromosomes, while males have one X chromosome and one Y chromosome. Turner syndrome results when one normal X chromosome is present in a female’s cells and the other sex chromosome is missing or structurally altered. The missing genetic material affects development before and after birth.
About half of individuals with Turner syndrome have monosomy X, which means each cell in the individual’s body has only one copy of the X chromosome instead of the usual two sex chromosomes. Turner syndrome can also occur if one of the sex chromosomes is partially missing or rearranged rather than completely absent. Some women with Turner syndrome have a chromosomal change in only some of their cells, which is known as mosaicism. Women with Turner syndrome caused by X chromosome mosaicism are said to have mosaic Turner syndrome.
Researchers have not determined which genes on the X chromosome are associated with most of the features of Turner syndrome. They have, however, identified one gene called SHOX that is important for bone development and growth. The loss of one copy of this gene likely causes short stature and skeletal abnormalities in women with Turner syndrome.
Turner syndrome is most often diagnosed during fetal life, in infancy, during the late pre-teen period (8-12 years), or in late adolescence/early adulthood. The age of diagnosis has been decreasing with better awareness of TS in the medical community.
Usually, there is something ‘different’ about the girl or woman that makes the parent or the doctor investigate the possibility of TS.
A final diagnosis is made by a blood test, called a karyotype, which looks at the complete set of chromosomes of an individual. A karyotype analysis determines if one of the X chromosome pairs is missing from the full chromosome set, or if there are any structural differences in the X chromosomes.
Before birth, a diagnosis of TS may be made by a maternal serum screening, by taking a sample of amniotic fluid or other fetal tissue to look at the fetal karyotype or an ultrasound. Because ultrasound and maternal serum screening (blood tests) are not 100% reliable, genetic karyotype testing is essential after the baby is born so that the diagnosis of TS can be confirmed.
There are a range of health, developmental, social, and learning challenges which might affect girls and women with TS to different degrees, so it is important to diagnose TS as early as possible.
There’s no cure for Turner syndrome but many of the associated symptoms can be treated.
Regular health checks and preventative care and treatment are important for girls and women with Turner syndrome. This is because of the risk of complications.
Some hospitals have dedicated Turner syndrome clinics with a number of specialists, including:
- A paediatric endocrinologist – a specialist in conditions that affect the hormones of children and teenagers
- A psychologist – a specialist in managing emotional, behavioural and educational problems
- A gynaecologist – a specialist in treating conditions that affect the female reproductive system
- A geneticist – a specialist in genetic and inherited conditions
- A nephrologist – a specialist in kidney conditions who helps manage high blood pressure
- An ear, nose and throat (ENT) specialist – who monitors ear conditions and hearing alongside an audiologist
- An adult endocrinologist
- A cardiologist – a heart specialist
- An obstetrician – a specialist in pregnancy and birth
If a girl or woman is diagnosed with Turner syndrome, the following areas may be monitored throughout her life.
Hearing and ears
During childhood, middle ear infections (otitis media) are more likely to develop and need to be treated quickly.
About half of all women with Turner syndrome lose their hearing faster than normal age-related decline. This can reduce their ability to interact socially.
High blood pressure (hypertension) is quite common in women with Turner syndrome, so it’s important blood pressure is checked regularly and treated, if necessary. This may be related to underlying heart or kidney problems.
Thyroid function tests can be used to assess how well the thyroid gland is working, as girls with Turner syndrome have a slightly increased risk of having an underactive thyroid (hypothyroidism).
The glucose levels in your blood or pee may be checked to screen for diabetes, a lifelong condition that causes your blood sugar level to become too high.
Bone mineral density
Women with Turner syndrome have an increased risk of developing brittle bones (osteoporosis) in late adulthood.
Bone mineral density can be measured at regular intervals using a dual-energy X-ray absorptiometry (DEXA) scan to assess any change with time.
Growth hormone therapy
A specialist in hormone-related conditions (endocrinologist) will carry out tests and checks on a regular basis. They’ll also be able to recommend appropriate treatment, such as growth hormone therapy.
Girls with Turner syndrome are entitled to receive high-dose growth hormone therapy as soon as it becomes apparent that they’re not growing normally. It will help make them taller in adulthood.
Growth hormone therapy is a daily injection, started at around 5 or 6 years of age or later. It’s usually continued until 15 or 16, helping the girl gain on average around 5cm (about 2in) in height.
The National Institute for Health and Care Excellence (NICE) has produced guidance about somatropin, the growth hormone sometimes used to treat Turner syndrome. Studies reviewed by NICE found somatropin increased height by around 5 to 9cm (2 to 3.5in).
A number of different types of somatropin are available. The type used will be based on the needs of the individual following a discussion between the specialist and the girl and her parents, including any advantages and disadvantages of the treatment.
Treatment with somatropin should be stopped if:
- there’s not enough growth in the first year of treatment
- the girl is near to her final height and has grown less than 2cm (0.8in) in a year
- the girl is unable to continue taking the medicine because of side effects or because she refuses to take it
- the girl reaches her final height
Somatropin is usually given daily as a single injection. Parents can give the injection or the girl can be taught to do it herself. The dose will depend on the girl’s size.
Oestrogen and progesterone replacement therapy
Oestrogen and progesterone replacement therapy may also be recommended. Oestrogen and progesterone are the female hormones responsible for sexual development. Oestrogen also helps prevent brittle bones (osteoporosis).
In girls with Turner syndrome, the ovaries (female reproductive organs) do not work properly. As a result, the girl may not go through puberty and is likely to be unable to have a baby without help (be infertile).
Women with Turner syndrome usually need regular sex hormone treatment until they’re about 50. After this time, the body usually stops producing oestrogen and monthly periods stop. This is called the menopause.
Oestrogen replacement therapy is usually started around the time of normal puberty. In girls, this is around 11 years old. It may be recommended that oestrogen replacement is started earlier in gradually increasing doses. Treatment will be tailored to the specific needs of each girl.
Oestrogen triggers the changes that usually happen during puberty, such as breast development. It’s important for the health of the womb and bones (protecting against osteoporosis).
It can be given as a gel, tablet or patch. Low doses are used to start with and gradually increased to adult levels with time and age, to mimic normal puberty.
Progesterone replacement therapy is usually started after oestrogen therapy and will cause monthly periods to start. It also may be given alone or combined in a tablet or patch with oestrogen.
Most women with Turner syndrome are unable to have children (infertile). A minority will be able to conceive naturally, so girls and women with Turner syndrome should have access to sexual health and contraception advice.
Assisted conception techniques, such as egg donation and in vitro fertilisation (IVF), may be recommended for women with Turner syndrome who want to have children.
If a woman has Turner syndrome and becomes pregnant, she’ll need regular heart checks because the heart and blood vessels will be put under extra strain during pregnancy. It’s vital her womb is healthy and has developed fully during puberty for the pregnancy to be successful.
Some girls and women with Turner syndrome may develop psychological problems, such as low self-esteem or depression.
Doctors sometimes attribute these problems to physical appearance or infertility, but they’re more commonly related to difficulties understanding other people’s social behaviour and how to respond appropriately. Associated problems often arise at home, in school and in the workplace.
Psychological therapy, such as counselling or cognitive behavioural therapy (CBT), may be recommended.