Down syndrome is caused by a random error in cell division that results in the presence of an extra copy of chromosome 21.
The type of error is called nondisjunction (pronounced non-dis-JUHNGK-shuhn). Usually when one cell divides in two, pairs of chromosomes are split so that one of the pair goes to one cell, and the other from the pair goes to the other cell. In nondisjunction, something goes wrong and both chromosomes from one pair go into one cell and no chromosomes for that pair go into the other cell.
Most of the time, the error occurs at random during the formation of an egg or sperm. To date, no behavioral activity of the parents or environmental factor is known to cause Down syndrome.1,2
After much research on these cell division errors, researchers know that:2
The NICHD launched DS-Connect® as a safe and secure online registry for people with Down syndrome, their families, and researchers to share information and participate in clinical trials or research. As the registry grows, families and researchers learn more about Down syndrome and identify similarities and differences in the symptoms and treatment of people with Down syndrome from around the world. The information collected helps guide future research and treatment. Learn more about DS-Connect®: The Down Syndrome Registry.
Research shows that three types of chromosomal changes can lead to Down syndrome.
All related news