This case is a variation of a longer case in our collection titled "Murder or Medical Mishap? Death on the Metabolic Ward," which has a "murder-mystery" aspect to it.  In both versions of the 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 case is designed as a "clicker case" using personal response systems or "clickers" to engage students in a large classroom setting.  It is suitable for a second-semester general biology or anatomy and physiology course.