Down Syndrome Defined

Down syndrome (DS) is a chromosomal disorder that occurs early in fetal development. The name Down comes from Dr. John Langdon Down who first identified this disease in 1866. The word syndrome literally means “a collection of signs or characteristics”.

The infant is born with specific mental retardation issues and physical disabilities. Down syndrome is considered incurable and leaves the person with lifelong care issues but those who have this disease appear to carry out productive and healthy lives.


Down syndrome is caused by abnormal cell division, which occurs very early in the development of the fetus. The results of the abnormal cell division are that every cell in the body gains an extra chromosome. These extra chromosomes cause the body to develop differently than what occurs in fetuses with normal cell division.

There are three different types of Down syndrome

    The first type and the most common form of DS is known as standard trisomy 21. This type of DS is always an accident of nature and cannot be traced to a cause of any kind.

    The second type is a result of a genetic anomaly called translocation and is caused from direct inheritance from the mother or father.

    The third type of DS also called mosaic Down syndrome is caused when an extra chromosome 21 forms in only some of the cells.

For reasons that science does not yet understand the risk of having a child with Down syndrome increases when the maternal age is greater that 35 years. The age of the father seems to carry less significance in the occurrence of Down syndrome.

Diagnosis During Pregnancy

The possibility of Down syndrome is many times diagnosed during pregnancy. There are screening tests that can be done during pregnancy that do not diagnose Down syndrome but will point to the likelihood that the baby will have it.

Fetal ultrasounds can show physical defects that may indicate a problem such as Down syndrome. Additionally, the mother will have certain substances in her blood during pregnancy that can indicate the possibility of the syndrome. DS can be positively diagnosed during pregnancy by using amniocentesis to study the chromosomes of the fetus.

If DS is not detected during pregnancy, there are many signs and symptoms that make it recognizable at birth. Many children have noticeable features such as a flat face, thick neck and uncharacteristically small ears and small mouth.

The children also suffer from below-average intelligence and a host of health impairments. The health problems can include heart problems, intestinal problems, respiratory defects, and hearing impairments.

Interestingly, people with Down syndrome will resemble each other with similar characteristics that are indicative of DS. These people also carry the characteristics and mannerisms of their mother and father and will resemble their parents as well as any siblings that are born to the family.

Since people with DS have many intellectual and health problems, treating a person with DS is geared toward first identifying and treating health problems. As the child grows the focus moves toward treating occupational type problems that will allow the child to have a more productive and fulfilling life in society.