The actor/ singer/ comedian is best known for performing musical comedy with Stephen Lynch, most notably selling out Carnegie Hall in 2009. What most people don’t know is that Mark was diagnosed at age eleven with scleroderma, a crippling, often fatal disease. He has beaten the odds but denying the pain and fear associated with it left him with a coping mechanism just as insidious – an addiction to lying. Mark can be seen on the show A.N.T. Farm on the Disney Channel.