<p><strong>World Down Syndrome Day</strong>&nbsp;(<strong>WDSD</strong>) is marked each year on March 21 beginning in 2006. The 21st day of March (the 3rd month of the year) was selected to signify the uniqueness of the triplication (trisomy) of the 21st chromosome which causes&nbsp;Down syndrome.</p>

<p>Every year on March 21,&nbsp;<strong>World Down Syndrome Day</strong>&nbsp;is observed to create awareness about Down syndrome. It is a condition in which a child is born with an extra 21st&nbsp;chromosome.</p>

<p>source: internet&nbsp;</p>