A seven-year-old boy suffers from a rare genetic condition which means he cannot stop SMILING. <br /><br />Evan Clarkson was born with Angelman syndrome – a chromosome disorder which causes severe learning difficulties – and puts a permanent grin on his face. <br /><br />The easily excitable youngster always appears happy and smiles or laughs as a result of the rare condition, which affects fewer than 1,000 people in the UK.
