In this "clicker case," students assume the role of pre-med students participating in a summer internship. As interns, they diagnose several different genetic deficiencies of glycolytic pathway enzymes based on the biochemical activity of blood samples. In order to accurately interpret the blood test data, the students first complete a brief homework assignment before the case is presented. This assignment requires students to describe the reactants, products, and enzymes of the glycolytic pathway. The case reviews the process of glycolysis and its importance in the human body.  As the students work through the case, they are introduced to the physiological significance of isoenzymes and the regulation of glycolysis. The last part of the case is a mystery that reviews enzymatic defects and shows how misregulation of glycolysis can have lethal consequences. The case is designed as a "clicker case" using personal response systems (clickers) to engage students in a large classroom setting.  It is suitable for a second-semester general biology or anatomy and physiology course. A second, shorter version of the case without the "murder-mystery" element is also available in our collection under the title: "Monday on the Metabolic Ward: Adventures in Glycolysis."