This disease is called Down syndrome and is also known as Trisomy 21 because it happens "at" the 21st chromosome. It was discovered and named after a British physician called John Langdon Haydon Down who first studied it in 1866. It was called Mongolism at first because Mongolia is in Asia and they thought that Down syndrome people look like Asians. This disease is not one of those physically painful really gross ones that you don't want to read about. It is a genetic disease and has many symptoms such as mental retardation or slow mental development. …
