What is Down syndrome?
Down syndrome is a genetic condition that is characterised by typical features. It is caused by an abnormality in the genetic material and it affects all races and all economic groups equally.
Why do they think that our baby has Down syndrome?
Babies with Down syndrome do look slightly different from other babies and therefore they can usually be identified at birth. Some of the typical features include:
- eyes that slant upwards;
- tiny folds covering the inner corners of the eyes (epicanthic folds);
- small white flecks on the iris (Brushfield spots)
- a small nose with a broad, flat bridge;
- a small mouth which makes the tongue appear large
- small low set ears;
- a single crease on the palm of the hand;
- short hands and fingers;
- inclining pinkie
- wider gap between the big toe and second toe
- A slightly flattened appearance of the back of the head.
- Unusual looseness of the joints
- Poor muscle tone (hypotonia) making the baby feel and appear “floppy”
- Loose skin folds at the back of the neck
- Heart defects occur in about 50% of cases
- Eye defects occur in 60% of cases
- Hearing defects may occur and can affect speech and language
- Developmental delay (intellectual disability varies from mild to moderate)
Not all these traits mentioned are found in every child with Down syndrome. Like other children, children with Down syndrome resemble their parents, e.g. hair and eye colour but they also have some of the typical features of Down syndrome. Furthermore each person with Down syndrome is a unique individual and can vary enormously in appearance, temperament and ability. It is also important to note that a person’s appearance has nothing to do with his intellectual ability. Therefore a person who has more of these above mentioned characteristics, is not necessarily more intellectually impaired. Down syndrome is not diagnosed only on the basis of physical characteristics, it must be confirmed by means of a chromosome analysis. This is a special type of laboratory test performed on a sample of blood from the baby. Your doctor will be able to tell you more about this test.
Where does the name “Down syndrome” come from?
Down syndrome is named after Dr Langdon Down, the physician who first described its features in 1866. The word “syndrome” means “a collection of signs and symptoms usually found in combination.
What causes Down syndrome?
Down syndrome is caused by extra genetic material. The genetic material is present in every human body cell and is arranged in tiny structures called chromosomes. They are the building blocks, which give us our individual characteristics. For example they determine the color of our hair and our eyes and many other characteristics. Each human body cell contains 23 pairs (46) chromosomes, except the sex cells (egg cells of a woman and sperm of a man), which each contains only 23 chromosomes. Egg cells and sperm are formed by a special cell division process during which the chromosome pairs divide and only one chromosome of each pair is included in a sex cell. The egg cell and sperm therefore each receives only one copy of each chromosome pair. During fertilization a sperm of the father fuses with an egg cell of the mother. The fertilized egg cell then contains 23 pairs of chromosomes (46 in total). One chromosome of each pair comes from the father and the other one of each of the pairs from the mother. The fertilized egg cell divides rapidly in the womb and eventually the baby is formed. Each of the body cells of the baby also contains 23 pairs (46) chromosomes. When a blood sample of a baby is analysed in a laboratory, a photograph of the chromosomes is taken under a microscope. The chromosomes on the photo are then cut out, numbered and arranged according to pairs. Such a chromosome arrangement is called a karyotype. Note that the chromosomes are arranged and numbered according to a specific pattern, namely from large to small. One of the smallest chromosomes is numbered as number 21. It is the chromosome number 21 that is involved in the origin of Down syndrome.
It is important to understand that Down syndrome is not caused by anything the mother or father did or failed to do during the pregnancy.
There are different types of Down syndrome:
Trisomy 21 type of Down syndrome
Trisomy 21 is the most common type of Down syndrome and is the cause of approximately 90-95% of all cases of Down syndrome. Trisomy type of Down syndrome is not hereditary! In young mothers the chance of a second baby being born with Down syndrome is therefore very small. Trisomy 21 (also known as non-disjunction type) occurs when the two number 21 chromosomes fail to separate and both instead of one, become incorporated into either the egg cell or the sperm. This cell then has 24 chromosomes instead of the normal 23. This phenomenon of the chromosome not separating is called non-disjunction. With fertilisation, the sex cell of one of the parents (egg cell or sperm) with the two number 21 chromosomes (and therefore 24 chromosomes in total), fuses with the normal sex cell of the other parent (egg cell or sperm with 23 chromosomes) to form a fertilized egg cell with 47 chromosomes. When this fertilized cell starts to divide, it eventually develops into a baby who has an extra number 21 chromosome in each body cell and hence Down syndrome. Trisomy 21 may be caused by non-disjunction during the formation of either the egg cells of the mother or the sperm of the father. The chances of Trisomy 21 however seem to be increased in women in their late thirties and older.
The Mosaic type of Down syndrome
This type of Down syndrome is very rare, not hereditary and the chance of a second baby born with it is small. Mosaic type is also known as Mosaicism. This is caused by non-disjunction of the chromosome pair number 21 shortly after fertilisation. The cells of the person with this type of Down syndrome have a mosaic pattern. The result is that some cells contain an extra chromosome number 21 (and therefore 47 chromosomes) while the other cells contain only 46 chromosomes (the normal number). Such a baby may only show partial features of the condition. Some of these babies look less affected than other babies with Down syndrome, but not all of them do.
The Translocation type of Down syndrome
A baby sometimes has all the clinical symptoms of Down syndrome but only 46 chromosomes in every cell. With Translocation, the baby has a normal number of chromosomes but extra chromosomal material. In these cases it is found that, over and above a normal pair number 21, these babies also have an extra part of a chromosome number 21, attached to another chromosome, which usually is chromosome number 14. This is called translocation type of Down syndrome. This type of Down syndrome can be hereditary! Either parent can carry a translocation without showing any symptoms. In this case the risk to have another child with this type of Down syndrome for the parents concerned, or for other members of the family, can be quite high. It is strongly advised that a chromosome test is done on both parents and that they seek genetic counseling if they plan further pregnancies. It is important to remember that the type of Down syndrome that is diagnosed makes no difference to the eventual development and potential of the child.
Why did this happen to us?
Down syndrome can occur in any marriage, to people of all races and religions. It is not caused by food or medicine taken or by any other event e.g. an accident during pregnancy. Neither of the parents is to blame and therefore you have no cause to feel guilty or blame your spouse. Try not to listen to superstitions and unlikely explanations given by well intentioned people.
“My husband left me soon after they told us Thabo had a genetic condition called Down syndrome. My husband said the ancestors were cross with me and were punishing me for something I did wrong. Today I know that that is not true and that I did not do anything wrong!” Eveline
“I thought that our daughter had Down syndrome because of the headache and pain tablets I took during my pregnancy. Little did I know then that Down syndrome arises at birth and that nothing I did during my pregnancy could have changed what happened on the day of conception. It took time for me to explain it to my extended family members and up to today some of them still think I am to blame.” Tina
“My whole family blamed me for the thing which happened to us. They said I slept around with different men or that I laughed at a child with a disability and that that is the reason why God is disappointed in me and decided to give me a child with a disability as well. It took me a long time before I found out the real reason why Rosinah, my daughter is different from other children.” Maria
“In the beginning I kept on asking “Why has this happened”, and still today, do not know the complete answer to that. A doctor told me that it might be because Steven was our third boy child, which of course is a myth and mistruth. What I do know is having Steven, has enriched our lives in so many ways and I would never change what has happened for all the money in the world!” Vanessa
What are the chances of having another child with Down syndrome?
About one in every 600 babies born in developing countries and one in every 1000 born in developed countries has Down syndrome. Any father’s or mother’s chance to have another child with Down syndrome is exactly the same as another father or mother of the same age. However, research has shown that if a couple already has a child with Down syndrome or if a mother is 35 years or older, the risk of having another child with Down syndrome slightly increases.
Why does the risk of having a baby with Down syndrome increase with the mother’s age?
The most likely explanation is the following: All the egg cells of a woman have already been formed when she was born as a little girl and these egg cells are found in an immature state in her ovaries (unlike men who produce new sperm from puberty onwards). In the case of women, after puberty only one egg cell matures each month and is released at ovulation. Therefore by the time the woman is, for example, 38 years old, her egg cells are also 38 years old. Ageing is therefore likely to have had an effect on the egg cells and the way the chromosomes divide when egg cells are formed. Today many older mothers have a prenatal test done to test for Down syndrome and other defects that can be detected before birth. Therefore, 80% of babies with Down syndrome are nowadays born to mothers younger than 35 years of age as women in this age group give birth to more babies overall and have had no reason to suspect that their babies would be affected.
Can Down syndrome be prevented?
Down syndrome itself cannot be prevented by special medicine or medical intervention since it is caused by a change in the chromosomes. Neither can this change be reversed in an individual with the disorder. Down syndrome can not be cured.
Can Down syndrome be detected?
Down syndrome can be detected during pregnancy in the fetus (unborn baby). Before a prenatal test is done it is advised that both parents seek counseling. A genetic counselor will be able to inform them about Down syndrome and the risk associated with the test. The counselor will also be able to inform them of their specific risk of having a baby with Down syndrome. A routine maternal blood screening to determine the risk of the baby to have Down syndrome can be performed at 15 – 20 weeks of pregnancy but detects only about 60% of all cases. Another prenatal test is called an amniocentesis and is 98% accurate. This test is usually performed at the 15th or 16th week of pregnancy, but in certain cases it is done as early as 13 weeks or as late as 22 weeks. For this test, some of the amniotic fluid that surrounds the fetus (and in which cells shed by the fetus are found), are collected and sent to a laboratory for a chromosome analysis. Amniocentesis involves a small but significant risk of miscarriage. For this reason an amniocentesis is usually performed only if the mother is running a high risk of having a child with Down syndrome or any other genetic disorder that is detectable before birth. The result of the chromosome analysis after an amniocentesis may only be available after two to three weeks, since these cells must first be cultured (multiplied) before they can be analysed. In that time it is wise for prospective parents to gather information about Down syndrome in order for them to make an informed choice. Other tests such as the Chorionic Villi Sampling and Nuchal Translucency Ultrasound can be performed earlier on during pregnancy but are not yet routinely used in our country. If the result of any of these tests indicates that the baby might have Down syndrome, the parents are informed of this. They can then discuss the matter with their doctor or a genetic counselor.
The decision of whether to continue with the pregnancy or to have it terminated rests solely with the parents. The counselor will, however, be able to give additional information on the genetic aspects and implications of having a child with Down syndrome, and refer the couple to other sources for advice and help, if necessary.
Should we go for genetic counseling?
The following people may be at a greater risk of having a child with Down syndrome and are advised to consult their family doctor, a specialist or a genetic counselor:
- Women in their late thirties or older, who are pregnant or are planning to have a baby;
- Couples who have already had a child with Down syndrome; and
- Couples with a family history of Down syndrome.
Where can we go for genetic counseling?
There are genetic counseling clinics in all the major centers of South Africa such as certain large hospitals and Universities with a Department of Human Genetics. The Sub-directorate Human Genetic Services of the Department of National Health employs genetics nurses at their provincial offices, who are trained to advise families affected by Down syndrome (or any other birth defect). They will arrange for you to receive genetic counseling and, if necessary, that prenatal and/or other tests are done.
Is there a cure for Down syndrome?
Down syndrome cannot be cured! It is an irreversible condition. However there is much you can do to help your baby develop the qualities and abilities he is born with to his maximum potential. Professionals are encouraged to refer families for necessary tests as early as possible in order to detect complications (heart, hearing and eye defects) which can be treated to improve the quality of life of the baby with Down syndrome. Early intervention and stimulation programmes have been developed to encourage the child to reach his full potential. It is very important to realise that children with Down syndrome are born with many qualities and abilities. It is up to the parents and caregivers to see that these are developed to the fullest. Internationally many products namely Alternative Targeted Nutritional Interventions are on the market claiming to improve the function and even in some cases cure the condition and/or the intellectual disability of the person with Down syndrome. Down Syndrome International and also Down Syndrome South Africa and all its affiliates do not recommend the use of any treatments or substances that have not been scientifically evaluated for both safety and effectiveness. At the time of publication of this booklet, none of the products currently marketed as Targeted Nutritional Interventions, or similar, in any country, have been shown to be either effective or safe. Although intensive international research is currently undertaken none of the products have been subjected to appropriate double-blind trials. Little is known about the side-effects of these formulas and the levels of some ingredients could be dangerous, especially for infants and small children. It is a natural response of parents to do whatever they can to better the quality of life of their children. Most of these products however are expensive and/or require intensive and time consuming efforts from the family members. As a family we want to encourage you therefore to carefully weigh all the options, risks and implications for your family and make an informed choice when deciding on therapies and treatment for your child.
Does our baby have different needs?
In the beginning your baby will need to be cared for just as any other baby would which means that he needs to be fed, changed, bathed, loved, played with, etc Throughout his life make sure that you treat your baby and child with Down syndrome like you would treat all your other children. Children with Down syndrome benefit from and prosper in a loving caring family environment. Your baby will tend to be slow to respond to you. However, you will find that if you cuddle and handle your baby regularly and lovingly, he will eventually respond and you will both benefit from the contact. When your baby grows up you would need to assist him in reaching his milestones. This is discussed later in this booklet under the developmental questions.
Will our baby be healthy?
The health of babies in general differs from baby to baby. However babies with Down syndrome seem to have an increased risk of having some congenital anomalies and developing certain medical problems. Most of these are however either treatable or correctable.
- Many children with Down syndrome have a weaker immune system and because of this, you may find that your baby is more prone to colds, infections and stomach upsets than other babies.
- The incidence of congenital heart disease is quite high among babies with Down syndrome. The mildest forms may improve with time, but corrective surgery is often necessary. Fortunately, this kind of surgery has a very high success rate.
- As children with Down syndrome often have an abnormal thyroid function, it is advisable to have your child’s thyroid function checked at intervals. Routine testing should be done at birth, or soon after, at six months and then yearly after that. Thyroid treatment is usually very successful.
- The nasal passages of a baby with Down syndrome are narrow and easily blocked. Keep your baby’s nasal passages clear to prevent mouth breathing. The nose, throat and chest are particularly prone to infection. In severe cases prescribed drops can be used for a while or use a saline solution twice daily (1/4 teaspoon salt per one cup sterile water) when necessary. When dropped into his nose, it will cause your baby to sneeze, clearing the passages.
- Some degree of hearing loss is common, most often due to frequent ear infections. Adequate hearing is critical to the development of good language skills, so periodic medical check-ups are necessary. Any suspicion of an ear or eye infection, hearing loss or a squint should be treated or corrected as soon as possible.
- Your baby may also experience more skin rashes, dry skin or sore lips. If your baby’s skin is dry and sensitive use a moisturizer e.g. aqueous cream, baby oil, lanolin cream, vitamin E oil or olive oil. As babies with Down syndrome often have poor circulation, a good rub with oil or cream and the bath towel after a bath is very beneficial.
- Vision problems are fairly common and an eye examination is recommended during the baby’s first year. Consult your doctor immediately if your baby’s eyes are sticky with thick mucus. However, if his eyes are only a little sticky, a gentle swab twice daily with lukewarm boiled water will suffice. It is important to swab his eyes from nose outwards, using each swab once only.
- Gastrointestinal abnormalities may be present at birth but can be dealt with through corrective surgery.
- A baby with Down syndrome has inefficient temperature control and does not respond well to changes in external heat. Therefore, keep your baby warm and well wrapped up in winter and cool in summer. Bath your baby daily but keep the water temperature moderate and do not leave him exposed for too long. When he is ill, a warm wipe down will suffice. When your baby gets older he may push off the blankets at night. One solution to this problem is to let your baby sleep in a warm babygro without blankets, or to make him a warm sleeping bag with a closed hem that fits him like a dressing gown. Keep him out of draughts and winds as this kind of exposure will affect his body temperature very quickly.
- As they get older, some children with Down syndrome tend to put on excess weight. Therefore, it is good to start early with a healthy, balanced diet – avoid too many sweets and refined starches in particular.
No individual with Down syndrome will have all the health complications, however every child needs good preventative medical care. With accurate diagnosis and appropriate interventions, most medical conditions can be easily managed. Teamwork between the family and doctors is vital to anticipate potential problems and provide specific and individual treatment should they occur. Families should remember that they have the right to ask a second and even a third opinion if they are not satisfied with the service of any professional working with their child. A regular, complete physical check-up every six months by your doctor is advisable for at least the first five years. Contact your nearest Down syndrome Association for a complete medical check list which includes growth charts, etc.