PA: Viewer discretion is advised.

HOUSE AND HIS TEAM GO TO EXTREME MEASURES TO DIAGNOSE A YOUNG BOY SO HE CAN IN TURN SAVE HIS DYING BROTHER'S LIFE ON "HOUSE" TUESDAY, AUGUST 21, ON FOX

Wilson prepares his 14-year-old leukemia patient, Nick, for a last-resort bone marrow transplant from his younger brother, Matty. With Nick's immune system completely wiped out from chemotherapy, Wilson is extremely cautious about keeping him healthy before the transplant. However, when Matty sneezes during a pre-op visit to his brother, Wilson knows that Matty is not healthy enough to donate. House and the team race to find out what is making Matty sick so that they can treat him quickly and allow him to donate healthy, uninfected bone marrow to his dying brother. With no other matching donors available, the team knows that Matty is their best shot at saving Nick's life. House decides they must purposefully make Matty sicker and use his developing symptoms as a method of narrowing the diagnosis field. As both brothers' conditions worsen and Nick has only days to live, the team must diagnose and treat Matty before it's too late for both of them. Meanwhile, Foreman is haunted by his mistake that killed a patient just one week earlier, and House wishes he could incur similar misfortune upon his new pet and nemesis, Hector, in the "Family" episode of HOUSE airing Tuesday, Aug. 21 (9:00-10:00 PM ET/PT) on FOX. (HOU-321) (TV-14 D, L)

Cast: Hugh Laurie as Dr. Gregory House; Lisa Edelstein as Dr. Lisa Cuddy; Omar Epps as Dr. Eric Foreman; Robert Sean Leonard as Dr. James Wilson; Jennifer Morrison as Dr. Allison Cameron; Jesse Spencer as Dr. Robert Chase.

Guest Cast: Dabier Snell as Matty; Jascha Washington as Nick; Adina Porter as Claudia; Thomas Mikal Ford as Scott; Greg Cipes as Salesman.