Down Syndrome

What is Down syndrome?

Down syndrome is a genetic disorder that causes mental retardation and physical defects. This is a disorder that is caused by having an extra chromosome at birth. A chromosome is the cell structure that contains genetic information.

A person with this syndrome is born with part or all of an additional copy of chromosome number 21.

This syndrome may cause certain physical characteristics, affect one’s physical and mental development, and cause health problems. However, your child can still lead a very active, successful, and happy life.

It is caused by the presence of an extra copy of chromosome number 21. This condition is called trisomy 21.

Symptoms

What are the physical signs and birth defects of Down syndrome?

Physical signs of this syndrome include:

• Short height (stature).
• Small head and ears.
• Short neck.
• Flat nose.
• Large tongue.
• Short, broad hands.
• Large space between the first and second toes.
• Muscles that seem flabby or have a low muscle tone.
• Low set ears.
• A single line (crease) across the palm of the hand (Palmar crease).

Children with this syndrome may also have:

• Developmental delays. They may be slow to crawl or walk.
• Learning disabilities.
• Poor coordination.
• Psychiatric conditions.

Some of the most common physical signs of this syndrome are upward slanting eyes, flattened facial features, ears that are small or unusually shaped, broad hands with short fingers and curved “pinky” fingers, and a small head. None of these physical differences cause health problems.

Some birth defects associated with Down syndrome cause more serious health problems. Babies who have this syndrome often have poor muscle tone or problems with their heart, stomach or eyes.

Intelligence ranges from low normal to very retarded (slow to learn), which can make learning and development more difficult.

Causes

Having a full or partial extra copy of chromosome 21 causes this syndrome. It is not known what causes this extra chromosome to occur.

Are some people more likely than others to have a baby who has Down syndrome?

If you have already had a baby who has this syndrome, you are more likely to have another one. For every 100 couples who have another baby, 1 will have another who has this disorder.

If you have been diagnosed with a chromosomal abnormality, you also have an increased risk of having a baby who has this syndrome.

Additionally, the risk of this syndrome increases with the age of the mother, as shown in this table:

Risk of Down Syndrome

Mother’s age	Chance of having a baby with Down syndrome
20 years	1 in 1,667
25 years	1 in 1,300
30 years	1 in 950
35 years	1 in 365
40 years	1 in 100
45 years	1 in 30

A person is more likely to have this syndrome if his or her birth mother was age 35 years or older. The risk of having a child with this disorder increases as the mother ages.

A person may also be more likely to have this syndrome if his or her birth mother had previously given birth to a child with Down syndrome.

Diagnosis

How is this syndrome diagnosed?

This syndrome can be diagnosed before and after a child is born. A woman can have prenatal screening tests that check for the likelihood of Down syndrome, but these screening tests do not diagnose this.

These can show if there are signs of Down syndrome that need more testing. These screening tests include a blood test and ultrasound. Tests that confirm a diagnosis include:

• Chorionic villus sampling (CVS). This test checks for chromosomal problems during weeks 9–14 of pregnancy.
• Amniocentesis. This test checks for proteins that could indicate birth defects, such as Down syndrome, during weeks 15–20 of pregnancy.

After a child is born, Down syndrome can be diagnosed based on physical appearance. A blood sample may also be taken to check the child’s chromosomes. This test can confirm the diagnosis of Down syndrome.

To find out if a baby has Down syndrome before birth, tests (such as amniocentesis and chorionic villus sampling  ) can check the tissue and fluid in the womb for the extra chromosome.

However, there is a slight risk that these tests can cause a miscarriage. Therefore, these tests are used only when there is a high chance of a genetic problem in the baby (such as a mother 35 years of age or older).

After birth, if the baby has any of the physical signs or birth defects of this syndrome, your doctor can test the baby’s blood for the extra chromosome.

Is there another way to tell if my baby might have Down syndrome?

A blood test called a triple screen (also called a quad marker screen if combined with other tests) can be done between the 15th and the 22nd weeks of pregnancy.

However, the test is most accurate when done between the 16th and 18th weeks. The screen cannot tell for sure whether your baby has Down syndrome or other chromosomal disorders, but it can tell if the risk is higher. If the test is positive, it means your risk of having a baby who has Down syndrome is higher.

But remember that many women with a positive screen have babies that do not have Down syndrome.

A negative screen means that the chance of Down syndrome is low. However, it doesn’t guarantee that a baby doesn’t have Down syndrome.

Should I be tested?

This decision is up to you. Some women feel better if they know their risk so that 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.

Treatment

Will my child need special medical care?

You may need to give your baby medicine. Your doctor will probably want to check your baby often to be sure that he or she is growing well and isn’t developing problems from birth defects.

Your baby may need to have physical therapy every week to help with building up muscle tone and coordination. Later on, speech therapy and occupational therapy (to help with issues such as language skills, hand-eye coordination and social skills) may be helpful for your child.

As with any child, children who have Down syndrome need regular medical care. Because children with Down syndrome often have problems hearing and seeing, your doctor may want to test your child for these problems at each visit. If there’s a problem, your doctor may refer your child to a specialist who can help him or her.

There are many possible treatments for Down syndrome. Your child’s treatment will depend on his or her current symptoms and any other symptoms that develop over time.

Treatment almost always requires a team of health care providers and support from other caregivers. Your child’s treatment plan may include:

• A heart specialist (cardiologist).
• A digestive system specialist (gastroenterologist).
• Physical therapy for bone or joint problems.
• Mental health providers or special education teachers to help with any behavioral or learning problems.
• A skin specialist (dermatologist).
• A brain specialist (neurologist) if your child has neurological changes, such as seizures.
• An eye specialist (ophthalmologist) if your child has eye problems, such as cataracts.
• A hormone levels specialist (endocrinologist) if your child has thyroid problems.
• A cancer specialist (oncologist) if your child develops leukemia.
• A sleep specialist if your child has sleeping problems.

Complications

What are the health problems that might affect my baby?

Some babies who have Down syndrome have 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.

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.

Some babies who have Down syndrome have problems swallowing, or they may have blockages in their intestines. Surgery may be necessary to fix these problems. Once they are fixed, they usually cause no further harm.

Some babies have eye problems, such as cataracts (cloudy lenses) or crossed eyes. Corrective lenses or surgery may be necessary to fix these problems.

Children who have Down syndrome may have colds, ear infections and sinus infections more often than other children. They are more likely to have thyroid problems, hearing loss, seizures and problems in their bones and joints. It’s also common for these children to be late in teething.

Will my child have learning problems?

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 retarded (slow to learn) in people who have Down syndrome.

If you keep your child physically healthy and provide therapy or treatment for his or her impairments, he or she will be better able to learn. With therapy, many children who have Down syndrome grow up to have jobs and live independently.

Follow these instructions at home:

• Learn as much as you can about your child’s condition.
• Give medicines only as directed by your child’s health care provider.
• Work closely with your child’s team of health care providers.
• Make sure that you have a good support system at home. This is very important.

Contact a health care provider if:

• Your child has new symptoms.
• You do not have enough support at home.

Down Syndrome in Adults: Staying Healthy

Are regular check-ups with a doctor necessary?

Adults who have Down syndrome need regular health care. Perhaps you have an adult child, brother or sister who has Down syndrome. Your relative needs the same preventive care as an adult who doesn’t have Down syndrome.

Also help your relative get checked for special medical problems that are more common in people who have Down syndrome. For example, a doctor should check your relative for thyroid disease, arthritis and problems with vision, hearing and the cervical spine.

How can I help my relative with Down syndrome lead a full life?

With a little planning, your relative can lead a more independent life. Common things to plan for include the following:

• Housing options such as group homes, supervised independent living or family-owned independent housing. It’s good to make plans for your relative to live independent of you.
• Work options such as sheltered workshops, supported employment and regular employment, with or without a job coach. Employment and social activities add increased meaning to life and may encourage responsible independence in your relative.
• Recreation options such as adult day care, the Special Olympics and other activities that involve exercise, hobbies and interests.
• Special estate planning, education beyond high school and self-help training.

My older relative who has Down syndrome is having some new problems. Could it be Alzheimer’s disease?

Symptoms similar to Alzheimer’s disease (a kind of dementia) occur at an earlier age in people who have Down syndrome (usually in their 30s). These symptoms include memory loss and personality changes.

Don’t immediately assume that the change in your relative is caused by dementia. There may be another reason for the change in behavior. Talk to his or her doctor about your concerns.

Some behavior changes	Possible cause
Talks to self	Stress; some self talk is normal
Withdrawal	Depression, stress, medical problem
Aggression	Depression, stress, medical problem

Seek Additional Information

• National Down Syndrome Society  
• Down Syndrome Research Foundation  
• National Association for Down Syndrome  
• National Down Syndrome Congress  
• DownSyndrome.com  
• La Leche League  
• National Institute of Child Health and Human Development  
• March of Dimes  

To find parent support groups in your area, contact:

• NDSS  at 800-221-4602 orwww.ndss.org  
• Down Syndrome Newsgroup  atwww.downsyndrome.com  

Bibliography

• Down Syndrome: Prenatal Risk Assessment and Diagnosis  by DS Newberger (American Family Physician August 15, 2000,http://www.aafp.org/afp/20000815/825.html  )
• Primary Care of Infants and Young Children with Down Syndrome  by RB Saenz (American Family Physician January 15, 1999,http://www.aafp.org/afp/990115ap/381.html  )