Structure of the dermis in type VIIC Ehlers-Danlos syndrome.

This report is the first to study histological, immunopathological, ultrastructural, and morphometric aspects of the abnormal structure of the dermis in Ehlers-Danlos syndrome, type VIIc. This disease, resulting from a defect in procollagen peptidase, resembles dermatosparaxis in animals. Dermal cells were abnormal in many aspects, including their large number, their strong argent affinity, and the occasional presence of oligocilia. Factor XIIIa-positive dendrocytes were, however, few in number. The stroma had many tears resulting from the absence of collagen bundles replaced by a loose meshwork of cauliflower fibrils. The mean collagen area, measured from fibrils, was similar to normal, and the individual values of this parameter were inversely related to the form factor that quantifies irregularity in fibril shape. Basement membranes were also defective, with an apparent paucity or focal absence of type IV collagen and laminin. The biology responsible for these many alterations in dermal structure is complex and not yet understood. The many morphological changes seen in Ehlers-Danlos syndrome, type VIIc, underscore the complexity of cell-matrix interactions in establishing a normal dermis.