Rock your Socks for Mencap this March to raise awareness and vital funds to support people with a learning disability across the UK. Down's syndrome is just one of many different types of learning disability. Most people have two copies of chromosome 21, while those with three copies of chromosome 21 have Down's syndrome. This is why we celebrate World Down's Syndrome Day on 21 March each year and encourage people to Rock Your Socks in March. World Down's Syndrome Day is an inclusive day for everyone and is a chance for us all to celebrate and support people with Down's syndrome and people with other learning disabilities.