MOLECULAR PATHOLOGY OF THE ELASTIC FIBERS

Elastic fibers form a network that contributes to the elasticity and resilience of tissues such as the skin. Histopathologic and ultrastructural abnormalities in the elastic fibers have been observed in several diseases of the skin and other tissues. Recent cloning of several genes involved in elastic fiber architecture has lead to the approach of the study of elastic fiber genodermatoses through molecular analysis. However, in genodermatoses, such as pseudoxanthoma elasticum, many of the genes encoding elastic fiber components have been excluded by genetic linkage analysis. In recent years, mutations in several of the genes encoding elastic fiber proteins have been demonstrated in other diseases. These include mutations in the fibrillin 1 gene in the Marfan syndrome, and genetic linkage of congenital contractural arachnodactyly to fibrillin 2, and, most recently, demonstration of abnormalities in the Menkes syndrome gene in X-linked cutis laxa. The first disorders to involve mutations in the elastin gene itself are, surprisingly, cardiovascular and neurobehavioral disorders, such as supravalvular aortic stenosis and Williams syndrome. These findings suggest that additional, as yet undiscovered, components of the elastic fiber network in the skin may hold the key to unraveling the molecular basis of the elastin-related genodermatoses.