Dan's Mother and father accompanied Dan to an appointment with Gregory House that had been set up, without House's knowledge, by Allison Cameron. House thought that Dan's symptoms were because of a concussion, but when he saw a myoclonic jerk, he admitted him.
House immediately suspected that Dan's Father wasn't really his biological father and surreptitiously secured DNA samples from both the mother and the father for testing. However, the test showed that neither parent was Dan's biological parent - he had been adopted, but they hadn't told Dan.
House confronted Dan's Mother about the deception, claiming that the medical history he had been given was useless. However, Dan's Mother assured him they had provided the birth mother's medical history. However, she could not tell House if Dan's biological mother ever had the measles,