Mark was a clinic patient in the Season 3 episode Informed Consent. He is the father of Ali. He was portrayed by actor William Charlton. Mark came to the clinic because he was suffering from headaches and aches all over his body. His daughter Ali came with him because they were going shopping for her prom. However, when Gregory House saw them, they were arguing about things and it was interfering with his examination. As a result, he started mimicking Mark to answer Ali's objections so that Mark could keep quiet. Dr. House noticed that Mark's voice was very nasal and when he pressed his fingers against his forehead above the eyes, Mark winced with pain. Dr. House soon diagnosed him with a common cold and sent him on his way. However, Ali found him entertaining and was soon calling him all