Down syndrome is a genetic disorder that is caused due to the presence of an extra set of chromosome 21. Down syndrome in babies can lead to developmental delays and intellectual disabilities and also increase the risk of heart diseases and thyroid. The symptoms of Down syndrome can affect the child physically and psychologically. Read on to know more about Down syndrome, its causes, symptoms, treatment, and preventive measures.
What is Down Syndrome?
Down syndrome is a condition where the person has an extra set of the chromosome 21, which is also the smallest human autosome. It means there are three chromosomes instead of two, which gives Down syndrome the name trisomy 21 (1). The genetic material from the extra chromosome affects the development of the embryo, causing a series of abnormalities that have a lifelong effect on the individual. Trisomy 21 was first accurately described by the English physician John Langdon Down in 1866. The condition has been called Down syndrome since then (2).
What Causes Down Syndrome?
Genetic abnormality of chromosome 21 is the fundamental cause for the condition. The defect itself can happen due to three reasons, leading to three types of Down syndrome:
- Multiple copies of chromosome 21: It is the most common form of Down syndrome, referred to as trisomy 21. Here, the baby is born with three copies of chromosome 21. The ovum and the sperm contain 23 chromosomes each, which are passed on to the embryo (baby). Thus the embryo or the zygote has 46 chromosomes (23 pairs). However, during cell division in the womb, the fetus abruptly develops an extra copy of chromosome number 21, which leads to trisomy 21. About 95% of babies born with Down syndrome have trisomy 21.
- Broken chromosome: The baby is born only with a broken chromosome 21. The broken part of chromosome 21 attaches itself to chromosome 14, leaving the chromosome 21 incomplete and the 14th chromosome with an extra attachment.
- It primarily happens due to genetic mutations in the egg or sperm, which means the father or mother, even though healthy, passed a gamete that contained an unusual genetic mutation. This type of Down syndrome is called Translocation Down syndrome, and it accounts for 3-4% of Down syndrome cases.
- Mixed trisomy: It is also called Mosaic Down syndrome and is very rare, constituting less than 1% of all Down syndrome cases. In this case, some cells of the body have three copies of chromosome 21, while the rest have a normal pair of chromosome 21. Those with this condition have the same characteristics as those with trisomy 21, but sometimes the symptoms are less severe. Down syndrome is fundamentally a result of a chromosomal abnormality. But no one precisely knows what causes the genetic mutation (3). However, the factors that seem to increase the risk have been identified.
What Are The Risk Factors For Down Syndrome?
Maternal age is the single most critical factor that can increase the chances of a baby being born with Down syndrome. Women above the age of 40 have the highest risk of having a baby with Down syndrome. The following table tells you about the chances of having a baby with Down syndrome at different maternal ages (2): Do note that women younger than 30 also have a risk of having a baby with Down syndrome, although it is significantly lesser compared to older women. The symptoms of Down syndrome vary from one individual to another, depending on several parameters other than the age of the mom.
What Are The Symptoms Of Down Syndrome?
Infants with Down syndrome can have the normal size and weight at birth. It is only eventually that the condition may get more pronounced. The symptoms of Down syndrome vary, but the following are the most typical ones (4): These are the general symptoms of the condition. If you observe these symptoms, take the baby to a doctor for a diagnosis.
How Is Down Syndrome Diagnosed?
There are two ways of diagnosing Down syndrome: before birth (prenatally) when a child is in the mother’s womb or after birth. The following are the salient points about the diagnosis (1):
1. Prenatal tests
These tests are divided into screening tests and diagnostic tests.
i. Screening tests
Screening tests merely look at the probability of the mother having a baby with Down syndrome. The advantage of these tests is that they can be carried out during the early stages of pregnancy and sometimes even before conceiving.
Blood test: A blood sample from both the parents is sent for laboratory analysis. The test checks for genetic mutations and other abnormalities that could increase the chance of the baby having Down syndrome. This test may not accurately predict Down syndrome, but can be done before conceiving, which is advantageous for high-risk women including those over the age of 40. Blood tests during pregnancy are performed at different stages for accurate diagnosis.
Ultrasound scan: This is like the usual ultrasound scan for expecting mothers. However, in this case, the doctor may look for specific features in the fetus such as a short nose, short neck bones, and heart defects that point towards Down syndrome. Image: iStock
Fetal MRI: It is done if the doctor is positive that the fetus could have Down syndrome. In this case, the mother is placed in the MRI machine and the fetus tested within the womb. Since MRI provides an accurate image of the body tissues, it can lead to a much precise diagnosis of Down syndrome. MRI is safe during pregnancy and will not have any impact on the developing fetus (5).
ii. Diagnostic tests
Diagnostic tests can accurately (almost a 100%) determine if the fetus has Down syndrome. On the downside, these tests may identify the condition only at 12 to 15 weeks at a later stage of pregnancy. Also, most of these tests are invasive, i.e., requiring a sample of the amniotic fluid or placenta, which increases the risk of miscarriage or passing an infection to the fetus.
Amniocentesis: A test where a small amount of amniotic fluid is drawn from the womb through a syringe (6). Amniocentesis is conducted in the second trimester, after 15 weeks of gestation. The amniotic fluid is sent for laboratory analysis to determine defects in the chromosome 21. A doctor may strongly recommend the test for expectant mothers over the age of 35, whose ultrasound or MRI indicate fetal anomalies.
Percutaneous umbilical blood sampling (PUBS): It is also called cordocentesis. A blood sample from the umbilical cord is collected for genetic testing. It is quite similar to amniocentesis, except here the blood is tested instead of the amniotic fluid. Chorionic villus sampling (CVS): A biopsy is performed to collect a tissue sample of the placenta, which is sent for lab testing. The test is conducted during the first trimester between 10-14 weeks of gestation.
2. Tests at birth
These tests are performed once the baby is born. A doctor may perform these tests whether or not the baby is diagnosed with Down syndrome before birth.
Physical examination: The doctor checks for tell-tale signs of Down syndrome such as the presence of a shorter nose bridge, slanting eyes, trouble closing mouth, tone of the muscles etc. Prenatal reflexes are also checked for detecting abnormalities. Image: Shutterstock Blood test: If the doctor suspects something wrong, or if the baby had a prenatal Down syndrome diagnosis, then a blood test is imperative. A rapid blood test can help detect Down syndrome within a week after birth.
Once diagnosed, the doctor will tell you about the further course of action.
Is There A Treatment For Down Syndrome In Babies?
There is no cure for Down syndrome, which is a lifelong condition (7). However, the health problems that accompany Down syndrome are often treatable through the following methods:
- Surgery: Conditions like congenital heart defects and intestinal problems can be rectified through surgery soon after the baby is born. 2. Medication: Chronic problems like thyroid issues and constipation are alleviated with the help of medicines that help the organs function correctly. 3. Adequate immunization: Vaccinating the baby as per schedule can reduce their susceptibility to infections.
- Tools and equipment: Glasses can correct vision problems while hearing aids can help the child hear properly. 5. Lifestyle changes: Since those with Down syndrome are prone to obesity, parents can consider specialized diets and exercises that help the little one maintain a healthy weight. Next, we tell you about the other related problems a baby can have along with Down syndrome.
What Are The Other Associated Problems Of Down Syndrome?
A baby with Down syndrome could suffer from several collateral health problems. Here are the most common ones (1):
Can You Prevent Down Syndrome In Infants?
There is no way to prevent Down syndrome since it is not known how to avoid the genetic defects that cause the condition (7). Late maternal age is one factor, which you may want to avoid. However, this does not guarantee prevention. Having a chromosome analysis and screening during pregnancy are a few ways to be prepared for a life with a child that has Down syndrome.
How To Manage Life For A Baby With Down Syndrome?
Children with Down syndrome are happy babies and are not entirely limited in any form and can perform daily tasks such as learning how to talk, walk, go to the toilet, and express their feelings through language. They achieve these milestones slowly when compared to other children of their age. However, with adequate care and management, infants with Down syndrome can grow to be like any other member of the society. Below are some ways that help you live a fulfilling life with a child having Down syndrome (8):
1. Support groups:
Contact a support group that can give you access to resources and information related to Down syndrome. It can help you understand your baby better. Infants with Down syndrome behave differently from their peers without the syndrome, making it hard for the parent to interpret their child’s body language and personality traits. You can find links to these support groups on the web, or ask your doctor or visit a child counselor about it.
2. Therapy
Therapy is vital for a child with Down syndrome since it allows him/her to fit into society better and can help through the formative years. Your baby will first need to undergo physical therapy that will allow them to crawl, roll, and stand during the early years. Therapy can help the child establish ideal body positions and movement styles that strains the body less while compensating for the low muscle tone. A language and speech therapy will help the child speak better, lay the foundation for better vocabulary and develop language skills later in life. A speech therapist can train the child with basic words and ways of using the facial muscles to make the right pronunciations. Babies with Down syndrome will also need emotional and behavioral therapy as they grow older. It can make things less frustrating in the teenage years when the child experiences a lot of physical and mental changes. Young adults with Down syndrome could benefit from occupational therapies. This therapy may start when your little one is young but gets more imperative during early adult years. The purpose of the therapy is to equip the child with skills and make them as independent as possible.
3. Motivation is vital
Motivation is the positive reinforcement that children with Down syndrome need throughout the growing years. It is important to not make the child feel handicapped or limited in any way, because of the disorder. Allow the child to play, mingle, talk, and socialize with other children. The more they see themselves as part of an ordinary group, the less they sense their limitations.
Eventually, it is parents who play a vital role in laying the foundation for the child’s bright future. Complete awareness and knowledge about the condition are the only way to manage it better. Next, we answer a few commonly asked questions about Down syndrome in babies.
