In House M.D., what genetic disorder does Thirteen eventually test positive for?

In House M.D., Thirteen eventually tests positive for Huntington’s disease.

Thirteen, whose full name is Remy Hadley, has a family history of Huntington’s disease because her mother died from it. Huntington’s is an inherited neurodegenerative disorder caused by a mutation in the HTT gene. It can affect movement, thinking, mood, and behavior, usually becoming apparent in adulthood.

The show uses Thirteen’s genetic testing as a continuing personal storyline rather than as a single weekly case. Her result changes how she thinks about relationships, future disability, medical decisions, and the limits of prediction. It also explains some of her guarded choices without reducing the character to her diagnosis.

Huntington’s disease is inherited in an autosomal-dominant pattern, meaning a person who carries the altered gene has a substantial risk of passing it to each child. The fictional storyline is not a substitute for genetic counseling, but it reflects the real significance of predictive testing for an inherited disorder.