Trisomy Awareness Month is observed in March to promote knowledge of trisomy conditions and to enhance support and care for individuals and families that are affected.
People with a trisomy condition have three copies of a particular chromosome in cells instead of the normal two copies. Normally, human cells contain 23 pairs of chromosomes, for a total of 46 chromosomes in each cell. A change in the number of chromosomes can occur during the formation of reproductive cells (eggs and sperm) or in early fetal development.
Down syndrome, also known as trisomy 21, is an example of a condition caused by trisomy. People with Down syndrome typically have three copies of chromosome 21 in each cell, for a total of 47 chromosomes per cell. Down syndrome occurs in about 1 in 800 newborns and is associated with intellectual disability, a characteristic facial appearance, and weak muscle tone (hypotonia) in infancy.
Additional examples of trisomy conditions are those caused by an extra copy of chromosome 13, 18, or the sex chromosomes X or Y. These conditions vary in severity, but they usually cause problems with growth, development, and function of the body's systems.
Trisomy Awareness Month is a time to raise awareness of the need to provide individuals with trisomy conditions and their families with support, not only at the time of diagnosis but throughout their lives.