Characterization of pseudoxanthoma elasticum-like lesions in the skin of patients with beta-thalassemia

Background: Pseudoxanthoma elasticum (PXE), an inherited disorder of unknow n pathogenesis, is characterized by elastic fiber mineralization, collagen fibril alterations, and accumulation of thread material in the extracellula r space. PXE-like clinical lesions have been described in patients with bet a -thalassemia. Objective and Methods: Dermal lesions in these two genetic disorders were c ompared by light and electron microscopy and by immunocytochemistry. Results: In both disorders, elastic fiber polymorphism, fragmentation, and mineralization were structurally identical. Elastic fiber mineralization in beta -thalassemia was associated with vitronectin, bone sialoprotein, and alkaline phosphatase, similar to what was observed in inherited PXE. Furthe rmore, abnormalities of collagen fibrils and filament aggregates were ident ical in both disorders. In both inherited and beta -thalassemia-associated PXE, unrelated gene defects seem to induce cell metabolic abnormalities tha t lead to identical clinical and structural phenotypes. Conclusion: Data indicate that patients with beta -thalassemia may undergo important alterations of connective tissues, a better understanding of whic h may help in preventing clinical complications.