House observes the sisters in their shared room. He notices that while they look identical, Maya (the one with lung failure) has a slightly different callus on her finger. He realizes she isn't just a gymnast; she’s a secret smoker. But that doesn't explain Lea's seizures.
The breakthrough comes when Chloe, the "healthy" one, finally collapses. House realizes the common denominator isn't what they are doing , but what they are taking . The Diagnosis: Dr. House: 2Г—3
had a delayed reaction that eventually triggered a cytokine storm. The Resolution House observes the sisters in their shared room
: House treats them as a single organism with three different "outputs." He theorizes that while their DNA is the same, their epigenetics —how those genes are expressed—have diverged due to secret lifestyle differences. But that doesn't explain Lea's seizures
: House’s team (Chase, Cameron, and Foreman) is stymied. Because they are monozygotic triplets, any genetic defect should be present in all three. However, their bodies are reacting differently to the same environment.
: Cuddy pressures House to find a solution before Maya’s lungs fail completely. Meanwhile, House is distracted by Wilson, who has started "triplet-dating" (dating a woman who is also a triplet), leading to a series of pranks about identity and individuality. The "Eureka" Moment