Research FAQs

Did I or my child's other parent cause my baby to have Down syndrome?

You did not cause your baby to have Down syndrome. Babies with Down syndrome are born to couples in all countries, all races, and all social and economic groups. Although we know that Down syndrome is caused by an extra chromosome 21, we do not know what causes that extra chromosome 21 to be packaged into the egg or sperm. Down syndrome is not due to any behavioral activity of the parents.

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What are you trying to find out through research?

First, we want to know more about what happens during the formation of egg cells and sperm cells that can lead to an extra chromosome being packaged into that egg or sperm. We are also looking for different factors in the health history of families that may be related to a person's likelihood for having a child with Down syndrome.

Second, we want to find out more about why children with Down syndrome have a higher risk for certain medical problems, such as heart problems and gastrointestinal problems. We are also looking for different factors in the health history of families that may be related to a person's likelihood for having a child with Down syndrome and a heart defect.

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Will these studies lead to prevention of Down syndrome in the future?

We hope that our research can add to the body of medical knowledge on Down syndrome and its related medical problems, such as heart defects. As doctors and scientists, we hope that our work will lead to practical clinical treatments. However, prevention is not the goal of this study. We value people with Down syndrome as productive and important members of society.

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Who is paying for this research?

The Emory Down syndrome Project is funded by the National Institutes of Health, through the National Institute of Child Health and Human Development. The Study of Down syndrome and heart defects is funded by the National Institutes of Health, through the National Heart, Lung, Blood Institute, and by the Sibley Heart Center, Children's Heathcare of Atlanta.

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Who will have access to the information families participating in research studies give you?

Only the very immediate study personnel have access to any personal information. Before any information is shared with others, all personal data such as names are removed so that participants cannot be identified.

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Will personal information from the research studies be shared with other people/government agencies?

Sometimes we work with other researchers interested in Down syndrome because they have specific expertise in areas that we do not. Before any information is shared, all personal identifying information (such as names) are removed so that families can not be identified in any way.

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How did Down syndrome get its name?

Down syndrome gets its name from the British doctor, John Langdon Down, who first identified the condition in 1866. The actual chromosomal nature of Down syndrome was discovered in 1959 by Dr. Jérôme Lejeune, a French researcher. However, Down's name remains associated with condition.

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Are children with Down syndrome born only to older mothers?

No. Although the risk of having a child with Down syndrome increases with age, a child with Down syndrome can be born to mothers of any age. About 75% of babies with Down syndrome are born to younger women. The chance of a woman under 30 having a baby with Down syndrome is less than 1 in 1,000 and increases to 1 in 400 for women who become pregnant at age 35.

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How many children with Down syndrome are born each year?

The incidence of Down syndrome is estimated at 1 per 800 to 1 per 1000 births. In 2006, the Center for Disease Control estimated the rate as 1 per 733 live births in the United States.

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Is the number of people born with Down syndrome increasing?

This is a difficult question to answer because the needed studies over time in large, stable populations have not been conducted. Many factors that influence the incidence of Down syndrome at birth change over time. These include factors such as methods to detect a pregnancy with Down syndrome, different cultural views related to pregnancy, and age of mothers becoming pregnant. Nonetheless, it appears that the incidence of Down syndrome in the US and Europe has remained stable relatively over time. Studies show that as the incidence of Down syndrome has risen slightly; this rise is in proportion to parents having children at slightly older age.

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What are the different types of Down syndrome?

People with Down syndrome have an extra chromosome 21. They have three copies of chromosome 21 instead of two copies, so Down syndrome is sometimes called "Trisomy 21".

About 95% of the time, the extra copy is due to an error made during the formation of egg or sperm. We have 46 chromosomes that come in 23 pairs. The process of separating the pairs of chromosomes at the time of egg or sperm formation is a delicate process. Sometimes an error occurs and the chromosome pair does not separate the right way and both of the chromosomes of a pair moves to the same cell. This error is called nondisjunction and leads to having either too many or too few chromosomes in the resulting egg or sperm. This kind of error can happen for any chromosome. But most of the time, a fetus that carries that extra chromosome cannot survive. This means that this type of error is the leading cause of pregnancy loss.

Sometimes this error occurs right after the formation of the fetus. In this case, some cells have the extra chromosome 21 and some do not. This is called mosaicism. This occurs in about 1-2% of people with Down syndrome.

Lastly, the extra chromosome 21 can be the result of a "translocation". It occurs in about 3-4% of people with Down syndrome. In this case, the extra chromosome 21 gets stuck to another chromosome. In about half of these situations, one parent carries the extra chromosome 21 in a "balanced", or hidden, form.

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