About Cornelia De Lange Syndrome Awareness Day
Cornelia de Lange syndrome (CdLS) is characterized by slow growth before and after birth leading to short stature; intellectual disability that is usually moderate to severe; and abnormalities of bones in the arms, hands, and fingers.
CdLS occurs in approximately 1 in 10,000 live births. It affects males and females equally, and is seen in all races.
The syndrome is named after Dutch pediatrician Cornelia Catharina de Lange, who described it in 1933.
Find out moreSimilar Observances
National Women and Girls HIV and AIDS Awareness Day
Find out the dates, history and traditions of National Women and Girls HIV and AIDS Awareness Day
Read More
Read More
Other Observances on May 9th 2026
Europe Day
Celebrates the anniversary of the Schuman Declaration in 1950, when the first step was made towards the creation of what is now known as the European Union
Read More
Read More


