This case tells the story of Elise, a college freshman whose identical twin sister has recently been diagnosed with schizophrenia. Elise is concerned about her own risk for developing this disease. Through her research and interactions with a physician, students are introduced to the topic of epigenetics and learn about the data supporting an epigenetic contribution to this psychiatric disorder. This case was designed for a sophomore-level molecular biology course for majors and could easily be adapted for an undergraduate genetics course. The case may also be applicable in a course that covers biological psychology. Students should have a basic knowledge of Mendelian inheritance patterns and a good understanding of the structure of DNA and its packaging within the cell (particularly the role of histone proteins and chromatin). The case also provides an opportunity for students to examine figures and graphs from the primary literature.