The past two decades have seen significant and unprecedented progress in human genetics owing to the advent of novel molecular biological technologies and major developments in computational methods. Dermatology has benefited from and, in some cases, led these advances. In this article, we review major discoveries in the field of inherited hair diseases, which illustrate the changes that genodermatology has undergone in recent years from a mostly descriptive discipline through the elucidation of the molecular basis of numerous disorders, up to the first attempts at translating these new findings into novel preventive and therapeutic tools to the benefit of our patients.