- The Down Syndrome Network of Greater Greensboro (DSNGG) invites you and your family to participate in its first annual 5K walk/run, in honor of World Down Syndrome Day! Our 3.21 Dash for Down Syndrome will be a traditional 5K fundraiser … with a little something extra! Run a spirited extra .11 mile to the second finish line for a 3.21-mile finish, signifying the three 21st chromosomes that characterize individuals with Down syndrome!