A Muscular Dystrophy Case Study Illustrating the Phenotypic Effects of Mutation

Mutations in genes can lead to a variety of phenotypes, including various human diseases. Students often understand that a particular mutation in a single gene causes a disease phenotype, but it is more challenging to illustrate complex genetic concepts such as that similar mutations in the same gene cause very different phenotypes or that mutations in different genes cause similar phenotypes. We originally designed this lesson to build off of the CourseSource lesson “A clicker-based case study that untangles student thinking about the processes in the central dogma,” but it can also stand alone. In our lesson, students read or listen to a real-life case study featuring a patient who doggedly pursues the underlying genetic cause of her own disease—muscular dystrophy—and stumbles upon a similar mutation in the same gene that gives an athlete the seemingly opposite phenotype: pronounced muscles. The lesson also leads the students to overlay their understanding of the central dogma and mutation on protein function and disease, compares muscular dystrophy to the disease progeria, and concludes with an ethical challenge. We tested the lesson as both an independent homework assignment, as well as a small group in-class worksheet and both formats were successful.