sentences:  The precise cause of diarrhea is unknown, and is speculated to relate to abnormal fat absorption and buildup of DGAT1 substrates in the intestinal mucosa.Mice with genetic disruption of the "DGAT1" or "DGAT2" genes have been made by the Farese laboratory at UCSF.Surprisingly, DGAT1−/− mice are healthy and fertile and have no changes in triglyceride levels.