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Down's syndrome

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Down’s syndrome affects your physical appearance, as well as your ability to learn and develop mentally. It is a lifelong condition, present from birth. Down’s syndrome occurs when a baby inherits an extra chromosome.
Brought to you by NHS Choices



Down’s syndrome is a genetic disorder named after John Langdon Down, the doctor who first identified it.

It affects approximately one in every 1,000 babies, which means that about 600 babies with Down’s syndrome are born each year in the UK. The condition tends to affect male and females equally. It is estimated that there are approximately 60,000 people with Down’s syndrome currently living in the UK.

Down’s syndrome affects your physical appearance, as well as your ability to learn and develop mentally. It is a lifelong condition, present from birth. Down’s syndrome occurs when a baby inherits an extra chromosome.

In the 1950s, many people with Down’s syndrome did not live past the age of 15. However, due to a better understanding of the condition and advancements in treatment and care, the average life expectancy of someone with Down’s syndrome is now 60-65 years of age.

The severity of Down’s syndrome symptoms can vary from person to person. There is currently no cure for the condition. However, there are treatments that can help someone with the syndrome to lead an active and independent life.


Symptoms of Down’s syndrome

Down’s syndrome can affect you in many different ways. Some of the most obvious symptoms are those which affect your physical appearance.

Physical features

People with Down’s syndrome tend to have a number of typical physical features. Some people with the syndrome may only have a few of these features, while others may be more severely affected.

Physical features of Down’s syndrome may include:

  • eyes which slant upwards,
  • small ears,
  • flat back of head,
  • protruding tongue,
  • small mouth,
  • flattened nose bridge,
  • white spots on the iris (the coloured part of the eye), known as Brushfield spots,
  • short fingers,
  • broad hands with a single crease across the palm,
  • loose skin on the back of the neck,
  • vertical skin folds (epicanthic folds) between the upper eyelids and inner corner of the eye,
  • loose joints (babies in particular may seem ‘floppy’),
  • poor muscle tone (hypotonia), and
  • low birth weight.


The physical development of children with Down’s syndrome tends to be slower than that of other children of a similar age. They may also be slower to develop socially and mentally. For example, it might take them longer to learn to speak, or to read. All people with Down’s syndrome will have some degree of learning disability, although some people are more severely affected than others.

If your child has Down’s syndrome, it will not stop them from developing at all. Many people with the condition can still learn all of the physical, mental, and social skills that most other people acquire; they just do it at a different pace.


Causes of Down’s syndrome

Down’s syndrome is a genetic condition that occurs because of an extra chromosome.

When a baby is conceived, it inherits genetic material from its parents. The genetic material is usually transferred to the baby in the form of 46 chromosomes - 23 from each parent.

Down’s syndrome is caused by a fault with a chromosome called the 21 chromosome. In most cases of Down’s syndrome, a child inherits an extra 21 chromosome, meaning they inherit 47 chromosomes instead of 46. When a person’s genetic make-up is unbalanced in this way, it can affect their physical and mental characteristics.

Types of Down’s syndrome

There are three different types of Down’s syndrome, which are caused by different faults with the 21 chromosome material. The different types of Down’s syndrome are outlined below.

  • Regular trisomy 21: Regular trisomy 21 Down’s syndrome occurs when all the cells in your body have an extra chromosome 21. There should be two copies of chromosome 21 in each cell, but people with regular trisomy 21 Down’s syndrome have three in each cell. Approximately 94% of people with Down’s syndrome have regular trisomy 21 Down’s syndrome.
  • Translocation: Translocation Down’s syndrome occurs when extra chromosome 21 material attaches itself to another chromosome. This means people with translocation Down’s syndrome have the normal two copies of chromosome 21, but also have extra chromosome 21 material from the chromosome that has attached itself. Approximately 4% of people with Down’s syndrome have translocation Down’s syndrome.
  • Mosaic: Mosaic Down’s syndrome occurs when only some of the cells have an extra, third, chromosome 21. Mosaic Down’s syndrome normally causes milder symptoms. Approximately 2% of people with Down’s syndrome have Mosaic Down’s syndrome

What will increase the chance of my child having Down’s syndrome?

There is nothing you can do to prevent Down’s syndrome from occurring.

If you already have a child with Down’s syndrome, there’s a 1% increased risk of you having another baby with the condition.

The chance of having a baby with Down’s syndrome increases when the mother is over 35 years of age. A 35-year-old woman has a one in 338 chance and a 45-year-old woman has a one in 32 chance.

However, approximately 80% of babies with Down’s syndrome are born to mothers under the age of 35. This is because women under this age make up the majority of the child-bearing population.


Diagnosing Down’s syndrome

All pregnant women, no matter what their age, should be given the choice to have their baby screened for Down’s syndrome.

Antenatal screening is a way of assessing whether your unborn baby could develop, or has developed, an abnormality or condition during your pregnancy.

Antenatal screening cannot diagnose conditions such as Down’s syndrome. However, what it does show is how likely it is that your baby will develop the syndrome. If the risk of Down’s syndrome (or any other condition) is shown to be high, further testing can then be arranged to help confirm whether your baby has the condition.

Antenatal screening for Down’s syndrome is carried out through a blood test and an ultrasound scan. This is known as a ‘combined test’.

Blood test

During a blood test, a sample of your blood will be taken and tested to check the levels of certain proteins and hormones. If your blood contains abnormal levels of these substances, you may have an increased risk of having a baby with Down’s syndrome.

Nuchal translucency ultrasound scan

During your pregnancy, you will have a number of ultrasound scans to check the development of your baby. An ultrasound scan is a painless procedure which uses high frequency sound waves to produce a picture of the inside of your body - in this case, the womb.

To screen for Down’s syndrome, you will need to undergo a special type of ultrasound, known as a nuchal translucency. This type of ultrasound works in the same way as a normal ultrasound scan, but it focuses on measuring the space between the spine and the nape of the baby’s neck.

All babies tend to collect fluid behind the neck. However, babies with Down’s syndrome normally have more fluid in the neck than normal. By measuring the thickness of fluid, your doctor can help to determine how likely it is that you will have a baby with Down’s syndrome.

Diagnostic tests

If the results of your antenatal screening or ultrasound scan suggest that your baby may be at an increased risk of a particular health problem or condition, such as Down’s syndrome, you may be advised to undergo further testing.

There are two types of test that can help to diagnose potential health problems or conditions while your baby is still in the womb. These are chorionic villus sampling (CVS) and amniocentesis.

It is important to be aware that both of these diagnostic tests can, in rare cases, result in complications. Your GP, or midwife, will be able to discuss all of your options with you in detail.

Chorionic villus sampling (CVS)
Chorionic villus sampling (CVS) involves having a small sample of the placenta (the organ in which the foetus grows and is protected and nourished) taken for examination. It can be performed after 10 weeks of pregnancy. The sample is taken either by passing a thin needle through the wall of your abdomen, or by passing a small tube through your vagina and the neck of your womb (cervix).

The needle, or tube, is put into the correct position using an ultrasound scan for guidance. The sample is taken and is later sent to a laboratory for testing. The results will be able to show whether your baby has Down’s syndrome.

Possible complications of CVS can include infection and heavy bleeding. Approximately 1% of women who have CVS also go on to experience a miscarriage. However, it is important to remember that the risk of miscarriage is very small, and most procedures cause no complications.

Amniocentesis involves taking a small sample of amniotic fluid (the fluid that surrounds the foetus in the womb) for examination. It is usually performed after 15 weeks and can be carried out until 22 weeks. The sample is taken by passing a needle through your abdomen and womb. The amniotic fluid can then be drawn out through a syringe.

As with CVS, the needle is guided into the correct position using an ultrasound scan. After the sample of amniotic fluid has been taken, it is sent to a laboratory for testing.

Possible complications of amniocentesis can include infection, or injury, to you, or your baby. As with amniocentesis, there is also a 1% chance of miscarriage. Amniocentesis is a fairly common procedure, and the risk of complications is low.


Being told that your baby may have Down’s syndrome can be difficult news to deal with. You will therefore be offered counselling to give you, and your partner, the chance to express your feelings and to ask questions about how this diagnosis may affect you both.

A counsellor will be able to make you aware of the different options available to you, allowing you to make a more informed decision about how to proceed with the pregnancy.

Diagnosis after birth

Once your baby is born, the initial diagnosis of Down’s syndrome is normally based on your baby’s physical appearance. Your doctor will assess your baby and look for the typical physical features associated with Down’s syndrome, such as eyes which slant upwards, or a flat back to the head.

If your doctor needs to definitively diagnose Down’s syndrome, they will arrange for a blood test known as a chromosomal karyotype. A sample of your baby’s blood will be taken and sent to a laboratory so that the chromosomes in the blood can be analysed. If the blood test finds that there is an extra 21 chromosome, your baby will be diagnosed with Down’s syndrome.

When should antenatal screening be carried out?

Ideally, you should undergo antenatal screening for Down’s syndrome by the end of your first trimester (13 weeks and six days). Most women are screened between 11 and 13 weeks. If necessary, it is possible to undergo screening up to 20 weeks, although you may require further blood tests.


Treating Down’s syndrome

There is no cure for Down’s syndrome, but there are a number of treatments that can help to improve quality of life, giving people with the condition the opportunity to lead healthy, active and more independent lives.

Emotional impact

In some cases, you may not find out that your baby has Down’s syndrome until they are born. Giving birth can be an exciting, scary and tiring experience, and finding out that your baby has this condition can be an unexpected shock.

If you have recently found out your child has Down’s syndrome, you may be experiencing a whole range of feelings, such as fear, sadness, or confusion. Some people feel numb about the situation, while others develop an almost immediate sense of protectiveness over their child.

Upon finding out that your child has Down’s syndrome, there is no right or wrong way to react. Finding out more about the condition may help you to get a better understanding about how it may affect your child’s life, as well as your own. Many parents find it reassuring to find out more information.

Support groups

If your child has Down’s syndrome, it is important to remember that you are not alone in your situation. There are thousands of people in the UK with Down’s syndrome. There are also many people, such as family members, carers, and friends, who have had experience of supporting and caring for those with the condition.

You may find it helpful to talk about your experiences with other families. They may be able to offer you advice and talk through any fears, or concerns, that you may have.

If you are not sure about how to find appropriate support groups, your GP should be able to put you in touch with a support group. You may also wish to visit the Down’s Syndrome Association website which provides information and support for people with Down’s syndrome, as well as their families and friends.

Early intervention

Early intervention programmes are specially designed for children with disabilities and learning difficulties. They focus on providing support to babies and children with Down’s syndrome - from when they are born, until they reach five years of age.

Early intervention programmes provide health care, educational programmes and treatments, such as speech therapy and physiotherapy. They also provide advice and support to the family who is looking after the child.

Early intervention is important because the earlier a child with Down’s syndrome receives the necessary help and support, the more independent and healthy they are likely to be later in life.

Your GP will be able to provide you with further information about early intervention. You can also read more about early intervention on the Down’s Syndrome Association website.

Support team

There are a number of different health professionals who will help to monitor and treat someone with Down’s syndrome.

  • Physiotherapist: A physiotherapist can help someone with Down’s syndrome to improve their range of movement. A child with Down’s syndrome will often have physiotherapy from a young age. For example, babies with Down’s syndrome may have poor muscle tone, so a physiotherapist can help them learn to roll over, sit up or walk.
  • Speech therapist: Children with Down’s syndrome may have problems learning to speak, so a speech therapist can help them to learn how to communicate more effectively.
  • Occupational therapist: An occupational therapist can provide people with practical support to help them live more independently. They can also help someone with Down’s syndrome to learn important social skills.
  • Dietician: People with Down’s syndrome may find it more difficult to control their weight than other people. A dietician will help someone with Down’s syndrome to devise a diet plan that is tailored to their needs in order to ensure that they are getting a healthy, nutritious, and well-balanced diet.
  • GP: Your GP will help you to deal with any more general health problems, and some of the day-to-day management of Down’s syndrome.
  • Social worker: People with Down’s syndrome may need help in overcoming some social problems, such as finding accommodation or applying for financial benefits. A social worker will help them to do this, allowing them to live more independently.
  • Audiologist: People with Down’s syndrome can sometimes experience hearing problems. An audiologist will be able to monitor your hearing so that any problems can be detected as soon as possible.
  • Ophthalmologist and orthoptists: An ophthalmologist is someone who specialises in treating eye conditions. Those with Down’s syndrome are at an increased risk of having eye problems, such as eye infections, or cataracts. An orthoptist often works with an ophthalmologist to treat eye conditions that involve problems with the movement, or focusing ability, of the eyes, such as squints (strabismus) or ‘lazy eye’ (amblyopia). See the ‘complications’ section for more information about the treatment of eye conditions in people with Down’s syndrome.

  • Paediatrician: A paediatrician is a doctor who specialises in the treatment of children. They often help coordinate all the different types of treatment that your child has.

  • Cardiologist: People with Down’s syndrome also have an increased risk of developing heart problems. Therefore, the health of their heart should be regularly checked. A cardiologist is someone who specialises in heart conditions.


Both children and adults with Down’s syndrome will have to go for regular check-ups so that their health can be monitored.

People with Down’s syndrome are more likely to develop health problems, such as cataracts, or hearing problems. It is therefore important to monitor their condition so that any health problems can be detected and treated as soon as possible.

People with Down’s syndrome will normally have their sight, hearing, and thyroid function (a test to see whether your thyroid is releasing the right amount of hormones into the body) regularly checked. Children with Down’s syndrome will also have their growth monitored.

Living independently

With help and support, many people with Down’s syndrome can live an independent and active life.

Many children with Down’s syndrome can go to mainstream schools. However, if your child is severely affected by Down’s syndrome, or you feel that they would benefit more from specialist schooling, there are a number of schools and other institutions that offer schooling specifically for those with special needs.

Many young adults with Down’s syndrome go on to pursue further education. Some also go on to gain employment, usually on a part-time basis, although this will depend on the individual. Many people with Down’s syndrome enter loving relationships, although they may need guidance and support when it comes to things such as contraception.

Men and women with Down’s syndrome tend to have a reduced fertility rate. This does not mean that they cannot conceive children, but it does make it more difficult. Those who do decide to have children will normally need specialist guidance and support, to help them cope with the physical and mental demands of a newborn baby.

If one parent has Down’s syndrome, the chances of their child having the condition are 35-50%. The chances are greater if both parents have the syndrome. The risk of miscarriage and premature birth is also much greater in women who have Down’s syndrome.

Although someone with Down’s syndrome may never be able to live completely independently, many people with the condition can live on their own, or with someone else. In most cases, people with Down’s syndrome move into property that is owned and staffed by a housing association. The staff can provide different levels of support, depending on the individual’s particular needs.


Complications of Down’s syndrome

Some people with Down’s syndrome experience very few health problems as a result of their condition. However, others can be more severely affected and require extra medical care and attention.

People with Down’s syndrome are at an increased risk of developing a number of different conditions and health problems. Some of these health problems may include the following.

Heart defects

Approximately 40-50% of children with Down’s syndrome will have a congenital heart defect. A congenital defect means that you have it from birth.

There are several different heart problems which can affect people with Down’s syndrome. One of the most common problems is known as an atrioventricular canal defect. This defect causes a hole to form within the heart, and can also result in problems with the heart valves, which help to regulate the blood flow in and out of the heart.

Other problems include ventricular septal defect. This is when a hole occurs in the septum (the wall that separates the right side of the heart from the left) in the lower part of the heart. This means the heart has to work harder to pump more blood around the body, which can sometimes cause the heart to become enlarged.

If your baby is diagnosed with Down’s syndrome, their heart will be carefully assessed so that any heart defects can be detected and treated as soon as possible. In approximately 30% of cases, the heart defect is serious any may require immediate surgery. In other cases the heart can be monitored and treated at a later date, if necessary.

Hearing problems

Approximately 50% of people with Down’s syndrome experience problems with their ears and, sometimes, their hearing.

Glue ear is a common condition for people with Down’s syndrome. It is caused by a build up of fluid in the middle ear. In some cases, the fluid thickens, making sounds appear muffled and distorted.

If your child cannot hear clearly, this may mean they find it more difficult to learn, or to interact with other children. If your child has glue ear as a result of their Down’s syndrome, they will normally be referred to an ear, nose and throat (ENT) specialist for treatment.

Sight problems

Approximately 50% of people with Down’s syndrome will also experience problems with their eyesight. Squints are common in people with Down’s syndrome, but can usually be successfully treated with the use of glasses. Occasionally, surgery may be used to correct a squint. Other eye problems can include:

  • lazy eye,
  • short sightedness,
  • long sightedness,
  • eye infections,
  • cataracts (when the lens in the eye clouds over),
  • nystagmus (when the eyes move uncontrollably, usually from side to side), and
  • keratoconus (when the cornea becomes thin and bulges out).

Thyroid problems

Approximately 10% of people with Down’s syndrome have problems with their thyroid gland. The thyroid gland is in your neck, and is responsible for controlling your metabolism (the rate at which your body uses up the energy). It does this by releasing thyroid hormones into the body.

Most people with Down’s syndrome have hypothyroidism, which means their thyroid gland is under-active because it does not produce enough hormones. Symptoms of an under-active thyroid can include:

  • lethargy,
  • weight gain,
  • slow physical and mental reactions,
  • muscle aches and weakness,
  • dry, flaky skin.

In rarer cases, people with Down’s syndrome can also develop hyperthyroidism, which means their thyroid is over-active by producing too much thyroid hormone. Symptoms of hyperthyroidism can include:

  • hyperactivity,
  • difficulty breathing,
  • mood swings,
  • difficulty sleeping,
  • lethargy,
  • muscle weakness, and
  • the need to pass stools, or urine, frequently.

Increased susceptibility to infection

People with Down’s syndrome tend to have an increased susceptibility to infection. This means that they tend to get conditions, such as coughs, colds, and chest, ear, and eye infections more easily than other people. It is thought that this increased susceptibility may be the result of an abnormality in the immune system.


Children with Down’s syndrome are at an increased risk of developing leukaemia - a form of cancer which affects the white blood cells (the cells responsible for protecting against, and fighting, infection).

Some research suggests that children with Down’s syndrome are 56 times more likely to develop leukaemia before the age of five, compared with children without the syndrome.

However, although they are at an increased risk, this does not necessarily mean that your child will develop the condition. Only one in 100 children with Down’s syndrome will go on to develop leukaemia.

Intestinal problems

Many people with Down’s syndrome experience some sort of intestinal problem. Some problems are mild, and are common in people both with, and without, Down’s syndrome. For example, constipation, diarrhoea, and indigestion are all common.

However, people with Down’s syndrome are more likely to experience more significant intestinal problems, such as small bowel obstruction, which stops food passing from the stomach into the large bowel.

Conditions such as imperforate anus (where a baby is born without an anal opening) or Hirschsprung’s disease (where the large bowel is unable to push faeces towards the anus) are relatively rare, but are slightly more common in children with Down’s syndrome. For example, approximately 2% of babies with Down’s syndrome develop Hirschsprung’s disease.


People with Down’s syndrome are more likely to develop dementia when they get older. Dementia causes you to gradually lose your mental abilities, such as thinking, remembering, and reasoning.

Compared to the rest of the population, people with Down’s syndrome tend to develop dementia at an earlier age. Approximately 40% of 50-59 year-olds with Down’s syndrome develop dementia.

Real stories

Victoria’s story

‘I’m going to celebrate what she can achieve’

Richard Davis’s daughter, Victoria, is seven. He talks about the impact Down’s syndrome has had on Victoria and family life.

“We didn’t know anything about Down’s syndrome when Victoria was born. We now know it’s the most common chromosome disorder.

“The people I’ve met who have Down’s syndrome are able to walk, talk, dress themselves and feed themselves. A lot of them lead an almost normal life.

“Victoria has made many friends at school. She visits other people’s houses without us and other children come here.

“She has lots of interests: she goes to ballet and gymnastics, and used to go trampolining. She also swims because that helps build up her muscles. People with Down’s syndrome have low muscle tone.

“Victoria has a sort of global delay because of the Down’s syndrome. She’s able to move around fairly quickly, but has very little sense of danger compared with her peers at school. So you have to keep stressing that something is dangerous, like crossing the road. You have to keep an eye on her all the time.

“Coordination is much, much slower and therefore she does miss out on things like games with the other children.

“She’s probably never going to go to Oxford or Cambridge and become a rocket scientist, but that’s not going to disappoint me because I didn’t do that either. Whatever she achieves is going to be great. I’m going to celebrate what she can achieve and not worry about what she can’t.

“Looking after Victoria has made our marriage stronger. In the beginning, we thought it was a major problem that we had to overcome, but it really hasn’t been.

“There are more trips to the hospital, and Victoria has more colds than an average child of her age. Her development is slower; you can definitely see that when she’s playing with her peers.

“Unfortunately, there was no parent support group in our area, so we asked the Down’s Syndrome Association to put us in touch with other new parents. We got together fairly quickly with six other parents whose child was born around about the same time. Talking to other parents about their experiences was very beneficial to us.”

Emily’s story

‘She’s brought an awful lot of fun into our house’

Emily, now 18, was born with Down’s syndrome. Her mum, Sarah, talks about the health issues they faced and Emily’s life today.

“I was quite a young mum when Emily was born. She had a few health problems and it was touch and go for the first few days.

“There’s a lot more understanding now about Down’s syndrome, although there’s still some way to go. People with Down’s syndrome are now included in television programmes and soaps, so you can see what they can achieve.

“It depends on your child as to whether they can go to a mainstream school or whether they need a bit of extra help. The special needs schools have a fantastic reputation academically, whereas a mainstream school can help with everyday behaviour and peer pressure.

“If they’re struggling, nobody’s going to benefit from the child being at a mainstream school. On the flip side, if they can manage at mainstream school and interact with their peer group, that’s really beneficial for later life.

“Most children with Down’s syndrome do everything their siblings do and can bring an awful lot of fun into the house because they’re so mischievous.

“Their sense of danger is pretty diabolical. They don’t see danger when they’re little, and a lot like to run off. Emily used to run in any direction she chose. They may be slow in some ways, but they’re fast at running once they’ve got the knack.

“She’s ridden a pony from the age of about four and competes with everybody else down at the local riding club.

“She’s at college at the moment. We hoped that she’d go off to residential college to get more independence, but she said she’s never leaving home, so we’ll see. At the same time, she’d love a flat of her own so she can be with her boyfriend or a group of friends.

“She’s had a few job offers already. One is in Worcester, which would mean moving away from home during the week, and she’s also been offered jobs locally. It’s a case of making sure she’s happy doing whatever she wants to do and has the independence she wants, but with the background care so it doesn’t fail.

“Emily’s looking at a perfectly normal life of growing up, getting married and living independently. Our job is to help her get there.”

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This article was originally published by NHS Choices

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