FAQs on Down Syndrome

Down Syndrome is a genetic condition caused by extra genetic material (genes) from the 21st chromosome. The extra genes cause certain characteristics that we know as Down syndrome. Individuals with Down Syndrome also have all the other genes given to them by their parents. As a result, they have a combination of features typical of Down Syndrome on top of the individual features from their parents. This includes some degree of mental retardation, or cognitive disability and other developmental delays. Some of the physical traits that are common but not always present are epicanthal folds over the eyes, flattened bridge of the nose, a single palmar crease and decreased muscle tone.

Down syndrome gets its name from the British doctor, John Langdon Down, who first clinically identified the condition in 1866. The actual chromosomal nature of Down syndrome did not become documented until 1959 by Dr. Lejeune. However, Down’s name remains associated with condition.

Also, though the term has nothing whatever to do with the physical direction “down”, Ann Fortis who has Down syndrome has coined the term “Up Syndrome” to provide a different perspective on the condition.

We don’t know what causes the extra 21st chromosome. We know that the extra 21st chromosome causes an extra dose of some proteins. Those proteins cause the typical features of Down Syndrome. We don’t know most of the proteins involved and how they cause Down Syndrome. We do know there is an association between a mother’s age and the chances of having a baby with Down Syndrome. No causes have been identified and proven, however.

In the usual circumstance, the chances depend upon the age of the mother. The odds of having a child with Down Syndrome at age 40 the odds are about 1 in 100, at age 35 are approximately 1 in 350 and under age 25, the odds are about 1 in 1400.

The chance of a woman with Down Syndrome having a baby with Down Syndrome is theoretically 50%. There is one documented instance of fertility in a male with Down Syndrome, the mother also had Down Syndrome. The pregnancy miscarried about half–way through.

Until recently, the answer was to offer amniocentesis to all pregnant women age 35 or older and to those women who had a previous child with Down Syndrome. Now some doctors recommend screening tests for all pregnancies.

No. Although the risk of Down Syndrome increases with age, a child with Down Syndrome can be born to a mother at any age. Although only 5–8% of pregnancies occur in women over the age of 35, they account for 20% of Down Syndrome births. Therefore, 80% of children with Down Syndrome are born to women who are less than 35 years of age.

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