This case study on hyperthyroidism tells the story of “Mae,” a mother with undiagnosed Graves’ disease. When Mae gives birth to a son weighing less than 4 pounds with tachycardia, the infant is immediately taken to the NICU. Students are progressively presented with lab results that show abnormal hormone levels, and then use their knowledge of negative feedback loops to identify which hormones are involved and investigate how the infant’s condition is directly related to an endocrine disorder that was undiagnosed in the mother. The case is designed as a review activity in which students apply their knowledge of normal physiology to analyze aspects of thyroid hormone pathology. The case is appropriate for a two-semester anatomy and physiology course taken by nursing, nutrition, athletic training, pre-occupational therapy, and other health majors in their first or second year. It could also be adapted for use in a physiology, pathophysiology, or human biology course, or for an advanced high school anatomy and physiology course.