The usual arduous path to the discovery and implementation of a new medical therapy is to start at the “bench” with the characterization of a molecular aberration in a specific disease (such as a type of cancer), assess its function, design a drug, and eventually bring that intervention to “bedside” through clinical trials. Rarely, if ever, does the path start at bedside with patients who share a profile of symptoms, lead back to the bench where the gathering of mutation data defines a new disease, and then move forward again to bedside. But on page 866 of this issue, Angulo et al. show that just such a route has led to the discovery of a new genetic immune deficiency disease, with a drug that is potentially at-the-ready for therapy (see the figure). The study emphasizes the power of exome (DNA coding regions) sequencing to identify causative mutations in rare diseases.