The latest fashions in skin disease.

The complex nature of epidermal tissue homeostasis is borne out by the range of diseases affecting this tissue. Indeed, mutations in proteins involved in intracellular integrity and cell-cell or cell-matrix adhesion can cause disease in an appropriate epidermal compartment. The most important realization in epidermal disease in the last two years has been that point mutations in key structural genes can result in filaments collapsing, cell cytolysis, or cell adhesion defects; and that these defects can result in severe human skin disease. Now that these associations have been made, the important next step will be to alleviate the suffering of these patients. Animal models will be an important part of these investigations; many molecules including growth factors, oncogenes, and cell adhesion molecules have been targeted to the epidermis of transgenic mice to investigate their role in disease. Such animal models should also elucidate the causes of diseases like psoriasis, a very common skin disease, the molecular basis of which remains elusive. Gene therapy involving the replacement of defective genes or local delivery of therapeutic molecules will be one of the main goals in alleviating these known epidermal diseases. Such protocols in the epidermis are aided by the relative accessibility of the skin and the presence of the "stem cells" in relatively accessible compartments. Indeed, as the last few years have shed much light on the genetic causes of epidermal disease, it is hoped that the next several years will prove as illuminating in the alleviation of these diseases.