Patterned disorders in dermatology

The skin gives us an opportunity to study pathologies unapparent in other systems such as patterned disorders. Among the best-identified patterns of skin disorders are the well-known lines of Blaschko, but other types of skin-patterned lesions have also been recognized. This short review will describe and discuss these different patterns and their pathophysiologic mechanisms, such as somatic mosaicism and X-chromosome associated mosaicism. Cutaneous patterned disorders are thought to be associated usually with inherited diseases per se, but in fact they are also reported in so-called acquired diseases. These cases suggest the existence of an underlying defect in a gene closely associated with the disease pathogenesis. The study of these acquired patterned disorders in the future may help us to understand the biologic foundations and pathogenesis of common human diseases.