In recent years, molecular genetic approaches to the study of human diseases have yielded unexpected insights into the pathophysiology of many dermatologic disorders, most recently, disorders involving hair loss (i.e., alopecia). In the future, it is anticipated that treatments for many of these disorders will be in the form of gene-based therapies. These approaches would not be possible without a fundamental understanding of the genes that underlie the respective genodermatoses, and how mutations in those genes give rise to the phenotype. In this review, we illustrate how these approaches apply to a rare inherited disorder involving hair loss in humans, known as papular atrichia, and discuss the corresponding mouse models, known as hairless and rhino. It is anticipated that these insights will someday lead to effective, rationally designed, genetic therapies for this group of psychologically devastating disorders, and eventually extend into more complex phenotypes seen in disorders such as alopecia areata and androgenetic alopecia.