The United Nations is on track to officially recognize an annual World Down Syndrome Day starting in 2012.

A resolution to establish the awareness day on March 21 of each year cleared a U.N. committee by consensus last week. Officials say it will be adopted by the international body’s General Assembly in December.

The United States is one of 78 countries supporting the effort, which is spearheaded by Brazil.

Supporters said the date — March 21, or 3/21 — is significant because Down syndrome occurs when a person has three copies of the 21st chromosome.

Advocates from around the world have honored Down syndrome awareness on March 21 for the last six years. Earlier this fall, more than 12,000 people signed a petition to request U.N. recognition in an effort to bring extra meaning to the day.

Per the resolution, member nations and private groups would be asked to promote Down syndrome awareness on the special day.

A similar U.N.-sanctioned day already exists to honor autism. In 2007, the international body named April 2 World Autism Awareness Day.

Correction: This article has been modified to reflect that 78 countries sponsored the U.N. resolution to establish World Down Syndrome Day.