Turner syndrome is a genetic disorder that affects about 1 in every 2,000 baby girls and only affects females.

A girl with Turner syndrome only has one normal X sex chromosome, rather than the usual two (XX).

This chromosome variation happens randomly when the baby is conceived in the womb. It is not linked to the mother's age.

Read more about the genetic cause of Turner syndrome. 

Characteristics of Turner syndrome

Females with Turner syndrome often have a wide range of symptoms and some distinctive characteristics. Almost all girls with Turner syndrome:

• are shorter than average
• have underdeveloped ovaries (female reproductive organs), resulting in a lack of monthly periods and infertility

As height and sexual development are the two main characteristics, Turner syndrome may not be diagnosed until a girl fails to show sexual development associated with puberty, usually between the ages of 8 and 14 years.

Other characteristics of Turner syndrome can vary significantly between individuals.

Read more about the symptoms of Turner syndrome and how Turner syndrome is diagnosed.

Treating Turner syndrome

There is no cure for Turner syndrome, but many of the associated symptoms can be treated.

Girls and women with Turner syndrome will need to have regular health checks of their heart, kidneys and reproductive system throughout their lives. However, it is usually possible to lead a relatively normal and healthy life.

Life expectancy is slightly reduced, but it can be improved with regular health checks to identify and treat potential problems at an early stage.

Read more about treating Turner syndrome.

Information about you

If you or your daughter has Turner syndrome, your clinical team will pass information about you/your daughter on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.

Find out more about the register.

Almost all girls with Turner syndrome will grow up to be shorter than average, with underdeveloped ovaries.

Girls with Turner syndrome will also have distinctive features and associated health conditions, some of which may be apparent from birth.

They may be born with swollen hands and feet, caused by a build-up of excess fluid in the surrounding tissues. This is known as lymphoedema, and it usually clears soon after birth.

Other features that may have developed in the womb include:

• thick neck tissue
• swelling of the neck (cystic hygroma)
• being a small baby
• heart conditions
• kidney abnormalities

Growth

Babies with Turner syndrome may grow at a normal rate until three years of age. After this age, their growth slows down.

At puberty (usually at age 8 to 14), a girl with Turner syndrome will not have the normal growth spurt, even with female oestrogen hormone replacement (HRT).

Girls with Turner syndrome are typically short in relation to the height of their parents. On average, adult women with untreated Turner syndrome are 20cm (8 inches) shorter than adult women without the syndrome. Treatment with additional high-dose growth hormone reduces this difference by about 5cm (about 2 inches) on average.

Read more about growth hormone treatment in Turner syndrome.

Ovaries

Ovaries are the pair of female reproductive organs that produce eggs and sex hormones. During puberty, a girl's ovaries usually begin to produce the sex hormones oestrogen and, once fully mature, progesterone. These trigger periods to begin.

Around 90% of girls with Turner syndrome will not produce enough of these sex hormones, which means:

• they may not begin sexual development or fully develop breasts without female hormone replacement therapy (HRT)
• they may begin sexual development but not complete it
• they may not start their monthly periods naturally
• it's likely they will be infertile (unable to have a baby) without assistance

Even though many women with Turner syndrome have undeveloped ovaries and are infertile, their vagina and womb develop normally. This means they are able to have a normal sex life following treatment with female hormones.

Most girls need hormone replacement therapy (HRT) with oestrogen from around 10 to 12 years of age to begin breast development, and about three years later with added progesterone to bring on monthly periods.

A minority (10%) of girls with Turner syndrome experience some physical changes naturally during puberty, but only a very small number (1%) become spontaneously pregnant.

Other symptoms

There are many other symptoms or characteristics that can affect girls and women with Turner syndrome. Some of these are listed below.

General features

• a particularly short, wide neck (webbed neck)
• a broad chest and widely spaced nipples
• arms that turn out slightly at the elbows
• a low hairline
• mouth abnormalities, which can cause problems with the teeth
• a large number of moles
• small, spoon-shaped nails
• a short fourth finger or toe

Eyes

• eyes that slant downwards
• droopy eyelids (ptosis) 
• a squint (strabismus)
• lazy eye (amblyopia)
• cataracts – cloudy patches in the lens at the front of the eye
• short-sightedness (myopia)

Ears

• low-set ears
• recurring middle ear infections (otitis media) and glue ear during early childhood
• hearing loss – this can occur in later life, but is often more severe and develops earlier than the normal age-related decline in hearing

Associated conditions

Turner syndrome is often associated with a number of other health conditions. Some of these include:

• heart murmur – where the heart makes a whooshing or swishing noise between beats; this is sometimes linked to a narrowing of the main blood vessel in the heart (the aorta) and high blood pressure
• kidney and urinary tract problems – this can increase the risk of developing urinary tract infections (UTIs) and high blood pressure 
• underactive thyroid gland (hypothyroidism) – this occurs in around 10-30% of women with Turner syndrome; regular blood tests are needed to detect it early before it causes symptoms
• high blood pressure (hypertension)
• osteoporosis (brittle bones) – in adult life, this may develop if oestrogen isn't adequately replaced by HRT
• scoliosis (abnormal curvature of the spine) – this should be screened for
• diabetes – a lifelong condition that causes a person's blood sugar level to become too high
• obesity – this increases the risk of type 2 diabetes and stroke, and can be reversed by following a healthy diet with regular exercise
• lymphoedema – this can occur at any age, not just in newborn babies
• bleeding in the digestive system – caused by abnormalities in the blood vessels in the intestines
• other digestive conditions – conditions such as Crohn's disease and ulcerative colitis are more common in females with Turner syndrome, but are still rare

Learning difficulties

Most girls with Turner syndrome have good language and reading skills. However, some have behavioural, social and specific learning difficulties.

Social intelligence

About a third of girls with Turner syndrome have problems understanding social relationships because of the way their brain develops.

This can make it difficult to sustain friendships and leads to relationship problems in later life, both at home and at work.

Spatial awareness and numeracy

Spatial awareness is the ability to understand where you are in relation to objects or other people.

More than 8 out of 10 females with Turner syndrome have difficulty understanding spatial relationships. This may cause problems when learning to drive or following directions on a map.

A similar number have some degree of difficulty learning or understanding maths. This is known as dyscalculia.

Attention and hyperactivity problems

Typically, girls with Turner syndrome will go through a phase in childhood that involves: 

• physical overactivity, such as constant fidgeting and restlessness 
• acting impulsively, such as breaking rules or having no sense of danger  
• having a short attention span and being easily distracted

Attention and hyperactivity problems usually begin when the girl is a toddler, but may not be a serious problem until the girl starts school at four or five years of age. Girls with Turner syndrome may have difficulty settling in class.

Medicines usually given to treat symptoms of attention deficit hyperactivity disorder (ADHD) may not be as effective in cases of Turner syndrome.

The physical hyperactivity usually reduces around the time the girl starts secondary school at 11 years of age, although problems with inattention can last longer, into the teens.

A girl with Turner syndrome only has one normal X sex chromosome, rather than the usual two (XX).

Everyone is born with 23 pairs of chromosomes. One pair of chromosomes – the sex chromosomes – determines the baby's gender.

One sex chromosome comes from the father and the other comes from the mother. The mother's contribution is always an X chromosome. The father's contribution can either be an X or a Y chromosome.

A baby girl usually has two X chromosomes (XX), and boys have an X and a Y chromosome (XY). The Y chromosome determines "maleness", so if it is missing – as in Turner syndrome – the sex of the child will invariably be female.

A female with Turner syndrome is missing part or all of one sex chromosome. This means she has just one complete X chromosome.

This chromosome variation happens randomly when the baby is conceived in the womb. It is not linked to the mother's age.

The syndrome can either be described as:

• classic Turner syndrome – where one of the X chromosomes is completely missing
• mosaic Turner syndrome – in most cells one X chromosome is complete and the other is partially missing or abnormal in some way, but in some cells there may be just one X chromosome or, rarely, two complete X chromosomes

Turner syndrome is usually identified during childhood or at puberty. However, it can sometimes be diagnosed before a baby is born using a test called amniocentesis.

Pregnancy and birth

Turner syndrome may be suspected in pregnancy during a routine ultrasound scan if, for example, heart or kidney abnormalities are detected.

Lymphoedema, a condition that causes swelling in the body's tissues, can affect unborn babies with Turner syndrome, and may be visible on an ultrasound scan.

Sometimes Turner syndrome is diagnosed at birth as the result of heart problems, kidney problems or lymphoedema.

Childhood

If a girl has the typical characteristics and symptoms of Turner syndrome, such as short stature, a webbed neck, a broad chest and widely spaced nipples, the syndrome may be suspected.

It is often identified during early childhood, when a slow growth rate and other common features become noticeable.

In some cases, a diagnosis is not made until puberty (sexual maturity) when breasts don't develop or monthly periods don't start.

Girls with Turner syndrome are typically short in relation to the height of their parents. But an affected girl who has two tall parents may be taller than some of her peers, and is less likely to be identified based on her poor growth.

Karyotypying

Karyotyping is a test that involves analysing the 23 pairs of chromosomes (strands of genes present in all human cells).

It is often used where Turner syndrome is suspected. The test can either be carried out while the baby is inside the womb by taking a sample of amniotic fluid (amniocentesis), or after birth by taking a sample of the baby's blood.

There is no cure for Turner syndrome, but many of the associated symptoms can be treated.

Health checks

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 at a faster rate compared with normal age-related decline. This can reduce their ability to interact socially. 

Blood pressure 

High blood pressure (hypertension) is quite common in women with Turner syndrome, so it's important that blood pressure is regularly checked and treated, if necessary. This may be related to underlying heart or kidney problems.

Thyroid gland

Thyroid function tests can be used to assess how well the thyroid gland is working, as girls with Turner syndrome are at a slightly greater risk of having an underactive thyroid (hypothyroidism). 

Glucose levels

The glucose levels in your blood or urine 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 osteoporosis (brittle bones) in late adulthood. Bone mineral density can be measured at regular intervals using a dual energy X-ray scan (DEXA scan) to assess any change with time.

Growth hormone therapy

An endocrinologist (specialist in hormone-related conditions) will be able to carry out tests and checks on a regular basis. They will 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 reduce short height in adulthood.

Growth hormone therapy is a daily injection started at around five or six years of age or later. It is usually continued until the age of 15 or 16, helping them gain on average around 5cm (about 2 inches) in height.

Read more about growth hormone therapy.

Somatropin

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 5-9cm (2-3.5in).

There are a number of different types of somatropin 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 is not enough growth in the first year of treatment
• the girl is near to her final height and has grown less than 2cm (0.8 inches) 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 perform the injection or the girl can be taught to do it herself. The dose will depend on the girl's size.

Read more about the side effects of somatropin.

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 is also important in preventing osteoporosis (brittle bones).

In girls with Turner syndrome, the ovaries (female reproductive organs) don't 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 will 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 known as the menopause.

Oestrogen

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

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.

Fertility

Most women with Turner syndrome are infertile (unable to have children). A minority will be able to coneive 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 will need regular heart checks because the heart and blood vessels will be put under extra strain during pregnancy. It's vital that her womb is healthy and has developed fully during puberty for the pregnancy to be successful.

Psychological therapy

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 are more commonly related to difficulties understanding other people's social behaviour and how to respond appropriately. Associated problems commonly arise at home, in school and in the workplace.

Psychological therapy, such as counselling or cognitive behavioural therapy (CBT), may be recommended.

Learning difficulties

Most girls with Turner syndrome have a normal level of intelligence, but some may have specific learning difficulties and require extra support.

It's important to seek help if your daughter is affected. Not all aspects of ability are affected equally, so an experienced psychologist should be asked to give an opinion.

You can speak to your GP or health visitor, or the teacher at your child's school or nursery. The school or nursery should follow guidelines about how to assess and meet your child's special educational needs to ensure she gets the appropriate support.

Read more about learning disabilities and education.