What Is Down Syndrome?

Down syndrome is a chromosomal condition that occurs when a baby is born with a partial or full extra chromosome 21. For every 700 babies born, approximately one baby will be born with Down syndrome. In the US, there are around 6000 children born with Down syndrome per year, according to 361 lawyers.

There are three types of Down syndrome: trisomy 21 or nondisjunction, mosaicism, and translocation. Trisomy 21 is the most common type of Down syndrome, accounting for around 95 percent of the cases. With this type of the syndrome, the 21st chromosome pair does not separate in either the sperm or egg. This results in the embryo having an extra chromosome 21. Mosaicism occurs when a mixture of two types of cells happen. This creates an extra chromosome 21. Around one percent of all cases are mosaicism. With translocation, the extra chromosome 21 will attach itself to another chromosome. This type of Down syndrome occurs in about four percent of cases.

A person with Down syndrome may or may not have many different features of the syndrome. These physical features can include a short stature, short limbs, low muscle tone, slanted eyes, small ears, and crooked or irregular teeth. The health problems associated with Down syndrome can include intellectual disability, eye conditions, celiac diseases, heart defects, dental or hearing problems, behavior problems, and hypothyroidism.

Diagnosing Down syndrome can be done before birth or after. Before birth, screening tests are completed to determine the chances of the child being born with the condition. Diagnostic tests have evolved over time allowing for more ways to test for Down syndrome before birth. Blood tests and ultrasounds are used to help to determine if the baby has the markers of the condition. Diagnostic procedures include amniocentesis and chorionic villus sampling. When a baby is born, Down syndrome is determined by checking for the physical traits and doing a karyotype test. A karyotype test is a chromosomal analysis that is done by examining the cells in a blood sample from the baby.

People with Down syndrome can still do most things that other people are able to do. Although there are cognitive delays, most of these delays are mild to moderate. More and more individuals are leading independent lives with limited assistance. With proper therapy and teaching, a person with Down syndrome can do almost all of the things that a person without the condition can do, such as play sports, have a job, do well in school, and care for themselves.