March 21. That’s Three twenty-one. These numbers are symbolic of the medical name for Down syndrome: trisomy 21. In humans, each cell normally has 23 pairs of chromosomes, which contain the person’s genetic makeup. In people with Down syndrome, the 21st chromosome has three rather than the usual two copies. The condition of there being three copies is known as trisomy; Down syndrome is the most common trisomy condition (please see our earlier blog post on Trisomy Awareness Month). Such seemingly tiny genetic variations can have a tremendous impact on a person. A prime example is the 23rd chromosome: females have two copies of the X chromosome and males have one X and one Y.
The theme for World Down Syndrome Day this year is “Leave No One Behind.” Says Anna Sands of Down Syndrome International, “All people with Down syndrome should have opportunities to live fulfilling lives and to be included on a full and equal basis with others across all aspects of society but the reality today is very different. People with Down syndrome face negative attitudes, low expectations, discrimination and exclusion.”