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Down syndrome is a genetic disorder that causes physical problems and intellectual disabilities. It is most often caused by the presence of an extra copy of chromosome number 21. This condition is called Trisomy 21.
Each person born with Down syndrome is different. Some have health problems. These could include heart disease, hearing problems, or problems with their intestines. Many begin treatment for medical issues early and live full, healthy, productive lives.
Symptoms of Down syndrome
There are many signs and symptoms of Down syndrome. Some people have different symptoms than others. Some have different problems at different points in their lives. Many people with Down syndrome share a distinct appearance. Common physical signs include:
- upward, slanting eyes
- flattened facial features
- protruding tongue
- short neck
- small head, ears, and mouth
- broad hands with short fingers
- decreased muscle tone.
Because of some of these physical features, children with Down syndrome often develop at a slower rate. This includes when they learn to roll over, sit, stand, and walk. They do reach these milestones, but it takes them longer. Physical issues in areas such as the heart, brain and GI tract can cause health problems.
In addition to physical signs, people with Down syndrome often have problems with thinking and learning. These problems include:
- short attention span
- poor judgment
- impulsive behavior
- slow learning
- delayed language and speech.
While these kinds of problems are common, they are rarely severe.
What causes Down syndrome?
Down syndrome is caused by a problem during cell division. This results in extra genetic material. The extra genetic material causes the features and problems of Down syndrome. There are 3 types of Down syndrome:
- Trisomy 21. In this form, the cell division issue happens during the development of the sperm or the egg. This gives the child three copies of chromosome 21 instead of the normal two copies. Up to 95% of people with Down syndrome have Trisomy 21.
- Mosaic Down syndrome. Some cells have an extra copy of chromosome 21 because of abnormal cell division in the embryo. This form is rare. Only 1% of Down syndrome cases are Mosaic.
- Translocation Down syndrome. Translocation (or shift) occurs before or at conception when part of chromosome 21 attaches onto another chromosome. It is the only form of Down syndrome that can be passed down from parent to child. This can happen even if the parent shows no symptoms of Down syndrome.
There are factors that increase your risk of having a child with Down syndrome:
- Advanced maternal age. The older the woman is, the older her eggs are. Older eggs are more likely to divide abnormally. At age 35, your risk of having a baby with Down syndrome is about 1 in 350. At age 40, the risk is 1 in 100. By age 45, your risk is 1 in 30.
- Already having a child with Down syndrome. If you have a baby with Down syndrome, you have a 1 in 100 chance of having another one.
- Being a carrier of a chromosomal abnormality. Both men and women can carry the translocation abnormality. If you are a carrier, you risk passing it on to your child.
How is Down syndrome diagnosed?
Screening for Down syndrome is a normal part of prenatal care. Screening options include:
- A blood test and ultrasound during the first trimester. The blood test looks for markers of abnormalities that could indicate Down syndrome. The ultrasound looks at “nuchal translucency.” It detects fluid at the back of the fetus’s neck. This could indicate an abnormality, including Down syndrome.
- A blood test in the second trimester. This is called the “triple screen” or “quad screen.” It also looks for markers in the mother’s blood.
- Integrated (combined) test. This approach uses the blood test and ultrasound from the first trimester and the blood test from the second trimester. It comes up with an overall risk rating of Down syndrome.
None of the screenings can diagnose Down syndrome. They only indicate that your risk of having a baby with Down syndrome is higher. Some women test positive in the screen but have perfectly healthy babies.
The only way to diagnose Down syndrome before birth is through diagnostic testing. This involves checking the tissue and fluid in the womb for the extra chromosome. This can be done through:
- Chorionic villus sampling (CVS). This takes a sample of the placenta during weeks 10 and 14 of pregnancy.
- Amniocentisis. This takes a sample of the amniotic fluid during weeks 14 to 18 of pregnancy.
- Percutaneous umbilical blood sampling (PUBS). This is also called cordocentesis. It takes a sample of the fetal blood in the umbilical cord during weeks 18 to 22 of pregnancy. It is the most accurate test.
There is a slight risk that these tests can cause a miscarriage. So these tests are used only when there is a higher chance of a genetic problem in the baby. This could be if the mother is 35 or older or if you have received an abnormal screening result. After birth, your doctor can test the baby’s blood for the extra chromosome. This is done if the baby has any of the physical signs or birth defects of Down syndrome.
Should I be tested?
This decision is up to you. Some women feel better if they know their risk. They can prepare themselves for the possibility of having a baby who has Down syndrome. Your doctor can help you understand your risks and consider the pros and cons of getting tested.
Can Down syndrome be prevented or avoided?
There is nothing you can do to prevent or avoid your child getting Down syndrome. However, your risk is lower if you have children at a younger age.
Down syndrome treatment
There isn’t one standard treatment for Down syndrome. A person’s treatment depends on their individual case. This includes their physical and intellectual needs, strengths, and limitations. Having Down syndrome puts your child at increased risk for a number of health problems. These need different forms of treatment. Treatments could be one-time (such as surgery) or lifelong (such as a special diet).
Treatment could start when your child is a baby. This could happen if he or she is born with a problem, such as a heart defect. They may be screened for other problems that commonly occur with Down syndrome. These include hypothyroidism, hearing loss, vision problems, blood disorders, and digestive problems.
Your child will most likely have a team of health professionals. This team will include doctors, specialists, and therapists. They will work together to give your child the treatment and therapy he or she needs. This will allow him or her to live as productive a life as possible. These include early intervention, therapies, and assistive devices.
Early intervention involves specialized programs and resources. These are provided to babies and toddlers with Down syndrome and their families. It usually lasts until the child turns 3 years old. Research has shown that early intervention improves outcomes for these children later in life.
There are a variety of therapies that can help a child with Down syndrome. These include:
- Physical therapy – exercises and activities that increase strength, improve posture and balance, and build motor skills. Many children with Down syndrome have low muscle tone. Physical therapy can be particularly helpful for them.
- Speech therapy – helps them communicate better and improve their language skills. Children with Down syndrome often speak later than other children. This therapy can help them develop those skills.
- Occupational therapy – adjusts everyday activities to the child’s abilities. This therapy teaches skills your child will use every day. These include eating, getting dressed, and caring for themselves.
- Behavioral therapy – helps your child cope with his or her condition. Complicated feelings and behaviors often go along with it. Children with Down syndrome get frustrated and can develop compulsive behaviors. They are more likely to have ADHD or other mental health issues. Therapy with a mental health professional can help.
An assistive device is any tool, technology, or piece of equipment that helps your child function more easily. This could include something as simple as a modified pencil that makes writing easier. Or it might be a special touchscreen computer that allows your child to communicate.
Living with Down syndrome
There are other health problems that often go along with having Down syndrome. Every person with Down syndrome is different. Your child may or may not have or develop any of these other conditions.
- Poor muscle tone. This makes it harder for them to learn to roll over, sit up and walk. Physical therapy can help with these problems.
- Heart defects. About half of babies who have Down syndrome also have a heart problem. An ultrasound exam of your baby’s heart will show any defects. Surgery may be necessary to fix the heart problems associated with Down syndrome.
- Digestive problems. Some babies who have Down syndrome have problems swallowing. Others may have blockages in their intestines. Surgery may be necessary to fix these problems. Once they are fixed, they usually cause no further harm. Children are more likely to have Celiac disease. This causes intestinal problems when they eat gluten, a protein in wheat.
- Hearing problems. Up to 75% of children with Down syndrome have problems with their hearing. They need regular hearing screenings and might need to have the problems corrected.
- Vision problems. Some babies have eye problems, such as cataracts(cloudy lenses) or crossed eyes. Corrective lenses or surgery may be necessary to fix these problems.
- Infections. Down syndrome causes problems with the immune system that makes it harder to fight infection. Your child may have colds, ear infections, and sinus infections more often than other children. It’s important for children with Down syndrome to receive all of their recommended vaccines.
- Blood disorders. Those with Down syndrome are more likely to have blood problems. These could include anemia (low iron) and polycythemia (high levels of red blood cells). Children with Down syndrome are more likely to develop leukemia (cancer of the white blood cells).
- Premature aging. Adults with Down syndrome can develop health problems normally caused by aging. These include dementia, memory loss, high cholesterol, diabetes, cataracts, and early menopause.
- Learning disabilities. At birth, it isn’t possible to tell how smart a baby who has Down syndrome will be. Intelligence ranges from low normal to very slow to learn.
Keep your child physically healthy. Provide therapy or treatment for his or her impairments. This will help them be better able to learn. With therapy, many children with Down syndrome grow up to have jobs and live independently.
Questions to ask your doctor
- Should I be tested when I’m pregnant to see if the baby has Down syndrome?
- Did I do something to cause my baby to have Down syndrome?
- How do I find out about early intervention programs? Who pays for them?
- What treatments will be most helpful for my child?
- How severe is my child’s intellectual disability?
- How can I help my child transition into adulthood?
- Will my child be able to have a job and/or live independently?
- What is the life expectancy of someone with Down syndrome?
Some of this content was developed by the University Centers for Excellence in Developmental Disabilities in CA (USC), MA (UMass Boston), IA (U of IA), KY (U of KY) and supported in part by the National Center on Birth Defects and Developmental Disabilities (NCBDDD) of the Center for Disease Control and Prevention through a cooperative agreement with Association of University Centers on Disabilities (AUCD). The opinions expressed are strictly those of the authors and do not necessarily reflect the opinions of the supporting organizations.
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.