Fibrillin immunofluorescence in pseudoxanthoma elasticum

Background: Pseudoxanthoma elasticum (PXE) is a rare heritable connective tissue disorder manifested by skin, ocular, and cardiovascular anomalies. The basic defect is unknown; however, the microscopic findings are indicative of defects in elastic fibers. Among the components of the elastic fibers are elastin and elastin-associated microfibrils. Objective: We assessed the fidelity of this fibrillar system in PXE with the use of antibodies to fibrillin, a major component of elastin-associated microfibrils. Methods: Using a well-established immunofluorescence assay, we studied fibrillin deposition in dermal fibroblast cultures from 16 patients with PXE. Results: Six of the 16 patients (37%) showed some abnormality of fibrillin deposition in fibroblasts derived from lesional skin. Fibroblasts from nonlesional skin displayed normal fibrillin immunofluorescence. The only sibship studied, however, was discordant for fibrillin immunostaining. Conclusion: Unlike the findings in Marfan syndrome, these data are not suggestive of causal fibrillin defects in PXE.