Down syndrome is a genetic condition caused when an unusual cell division results in an extra full or partial copy of chromosome 21. This extra genetic material causes the developmental changes and physical features of Down syndrome.
The term "syndrome" refers to a set of symptoms that tend to happen together. With a syndrome, there is a pattern of differences or problems. The condition is named after an English physician, John Langdon Down, who first described it.
Down syndrome varies in severity among individuals. The condition causes lifelong intellectual disability and developmental delays. It's the most common genetic chromosomal cause of intellectual disabilities in children. It also commonly causes other medical conditions, including heart and digestive system problems.
Better understanding of Down syndrome and early interventions can greatly improve the quality of life for children and adults with this condition and help them live fulfilling lives.
Each person with Down syndrome is an individual. Problems with intellect and development are usually mild to moderate. Some people are healthy while others have serious health issues such as heart problems that are present at birth.
Children and adults with Down syndrome have distinct face and body features. Though not all people with Down syndrome have the same features, some of the more common features include:
Infants with Down syndrome may be average size, but typically they grow slowly and remain shorter than other children the same age.
Children with Down syndrome take longer to reach developmental milestones, such as sitting, talking and walking. Occupational therapy, physical therapy, and speech and language therapy can help improve physical functioning and speech.
Most children with Down syndrome have mild to moderate cognitive impairment. This means that they have problems with memory, learning new things, focusing and thinking, or making decisions that affect their everyday life. Language and speech are delayed.
Early intervention and special education services can help children and teens with Down syndrome reach their full potential. Services for adults with Down syndrome can help support living a full life.
Down syndrome usually is diagnosed before or at birth. But if you have any questions regarding your pregnancy or your child's growth and development, talk with your doctor or other healthcare professional.
Human cells usually contain 23 pairs of chromosomes. One chromosome in each pair comes from the sperm, the other from the egg.
Down syndrome results from an unusual cell division involving chromosome 21. This unusual cell division results in an extra partial or full chromosome 21. This extra genetic material changes how the body and brain develop. It is responsible for the physical features and developmental problems of Down syndrome.
Any one of three genetic changes can cause Down syndrome:
Most of the time, Down syndrome is not passed down in families. The condition is caused by a random unusual cell division. This can happen during the development of the sperm cell or the egg cell or during early development of the baby in the womb.
Translocation Down syndrome can be passed from parent to child. But only a small number of children with Down syndrome have translocation and only some of them inherited it from one of their parents.
Either parent may have a balanced translocation. The parent has some rearranged genetic material from chromosome 21 on another chromosome, but no extra genetic material. This means the parent has no signs of Down syndrome, but can pass an unbalanced translocation on to children, causing Down syndrome in the children.
Some parents have a greater risk of having a baby with Down syndrome. Risk factors include:
Health concerns that result from having Down syndrome can be mild, moderate or severe. Some children with Down syndrome are healthy, while others may have serious health problems. Some health concerns may become more of a problem as the person gets older.
Health concerns can include:
Over the years, there have been advances in healthcare for children and adults with Down syndrome. Because of these advances, children born today with Down syndrome are likely to live a longer life than in the past. People with Down syndrome can expect to live more than 60 years, depending on how severe their health problems are.
There's no way to prevent Down syndrome. If you're at higher risk of having a child with Down syndrome or you already have one child with Down syndrome, you may want to talk with a genetic counselor before becoming pregnant.
A genetic counselor can help you understand your chances of having a child with Down syndrome. The counselor also can explain the prenatal tests that are available and help explain the pros and cons of testing.
The American College of Obstetricians and Gynecologists recommends offering the option of screening tests and diagnostic tests for Down syndrome to all who are pregnant, no matter what age.
Your healthcare professional can discuss the types of tests, advantages and disadvantages, benefits and risks, and the meaning of your results. If needed, your healthcare professional may recommend that you talk to a genetic counselor.
Screening for Down syndrome is offered as a routine part of care before the baby's birth, called prenatal care. Although screening tests can only tell your risk of carrying a baby with Down syndrome, they can help you make decisions about the need for diagnostic tests.
Screening tests include the first trimester combined test and the integrated screening test. The first trimester means about the first three months of pregnancy.
The first trimester combined test is done in two steps. These include:
Using your age and the results of the blood test and the ultrasound, your healthcare professional or genetic counselor can estimate the risk that your baby has Down syndrome.
The integrated screening test is done in two parts during the first and second trimesters of pregnancy. The results are combined to estimate the risk of your baby having Down syndrome.
A small amount of DNA is released from the placenta into a pregnant person's bloodstream. This cell-free DNA in the blood can be examined for the extra chromosome 21 material of Down syndrome.
For those at risk of having an infant with Down syndrome, the test can be done starting at 10 weeks of pregnancy. If the test is positive, diagnostic testing is usually needed to confirm that the baby has Down syndrome.
If your screening test results are positive or uncertain, or you're at high risk of having a baby with Down syndrome, you might consider more testing to confirm the diagnosis. Your healthcare professional can help you weigh the pros and cons of these tests.
Diagnostic tests that can identify Down syndrome include:
Couples who are being treated for infertility through in vitro fertilization (IVF) who know that they are at increased risk of passing on certain genetic conditions to their children may choose to have the embryo tested for genetic changes before it's implanted in the womb.
A physical exam is usually enough to identify Down syndrome in an infant in the first 24 hours after birth. If your healthcare professional thinks that your infant has Down syndrome, your healthcare professional orders a test called a chromosomal karyotype to confirm the diagnosis. Using a sample of blood, this test looks at your child's chromosomes. If there's an extra full or partial chromosome 21 in all or some cells, the diagnosis is Down syndrome.
Early intervention for infants and children with Down syndrome can make a major difference in improving their quality of life. Because each child with Down syndrome is unique, treatment will depend on your child's needs. Also, as your child gets older and enters different stages of life, your child may need different care or services.
For people with Down syndrome, ongoing services, including healthcare, education and life skills support, are important throughout life. Getting routine medical care and treating issues when needed can help keep a healthy lifestyle.
If your child has Down syndrome, you'll likely rely on a team of specialists that can provide medical care and help your child develop skills as fully as possible. Depending on your child's needs, your team may include some of these experts:
You'll need to make important decisions about your child's treatment, services and education. Build a team of healthcare professionals, teachers and therapists you trust. These professionals can help find resources in your area and explain state and federal programs for children and adults with disabilities.
You may find it helpful to look for a developmental pediatrician, a specialist with expertise about Down syndrome. Also, some areas have a child Down syndrome specialty clinic that offers a range of services in one place. These experts give special attention to needs and issues that are more common in people with Down syndrome. They can work together with your primary care professional.
As your child with Down syndrome becomes an adult, healthcare needs can change. Besides general health screenings recommended for all adults, ongoing healthcare includes evaluation and treatment for conditions that are more common in adults with Down syndrome. You may choose to visit an adult Down syndrome specialty clinic, if available.
Conditions common in adults with Down syndrome include:
In addition to meeting health needs, caring for your adult loved one with Down syndrome includes planning for current and future life needs, such as:
When you learn your child has Down syndrome, you may experience a range of emotions. You may not know what to expect, and you may not be sure of your ability to care for a child with a disability. Information and support can help ease these concerns.
Consider these steps to prepare yourself and to care for your child:
People with Down syndrome can live fulfilling lives. Most people with Down syndrome live with their families, in supported living settings or independently. With needed support, most people with Down syndrome go to mainstream schools, read and write, make decisions, have friends, enjoy an active social life, and have jobs.