HOMEOBOX GENES AND THE PATTERNING OF SKIN DISEASES

One of the continuing mysteries of dermatology in general, and dermatopathology in particular, is the regional nature of specific diseases, whether infectious, neoplastic or immunologic. It is common for a dermatologist to establish the differential diagnosis of a rash based on its local pattern, clinically or histologically. Thus, while patterning is fundamental to diagnosis and much has been made of this subject heuristically, the dermatology community has given surprisingly little attention to its mechanism. The molecular basis of pattern formation in the embryo has long been the search of developmental biologists (1). Recently this quest has identified a family of strongly conserved genes which, when mutated or experimentally manipulated, alter body and limb formation in the embryo. In this essay we provide a description of the homeobox gene family and present evidence for its involvement in development together with an extrapolation of these findings to the skin.