Novel genetic modifiers have been identified in epidermolysis bullosa, ichthyoses and other genetic skin diseases. These discoveries are not only relevant to rare single-gene traits. The discovery of the cause of simple traits is increasingly found to be of relevance to the understanding of more complex multifactorial diseases. For example, an ultra-rare disease, the uncombable hair syndrome and central centrifugal cicatricial alopecia, the most common form of scarring alopecia among women of African origin, have been found to be allelic conditions. Finally, this new knowledge is now systematically translated into novel approaches to the treatment of a steadily growing number of genetic skin disorders, rare and common alike, including hypotrichosis and psoriasis.