[Ehlers-Danolos syndrome: a disease of fibroblasts and collagen fibrils. Classification and electron-microscopic findings in five patients (author's transl)].

Five patients with Ehlers-Danlos syndrome (EDS) were classified according to clinical and genetic criteria and were examined by electron microscopy: two cases in Type I and one case each in Types II, III, and V were found. In all cases distinct ultrastructural changes were seen in the fibroblasts and the collagen fibrils whereas the elastic fibers were normal, as shown with special staining techniques. a) The fibroblasts were smaller, their cytoplasmic processes reduced in number and size, the endoplasmic reticulum was underdeveloped and their ribosome content was diminished. Also, cellular degeneration up to necrosis was found. In three cases intercellular substances were seen, possibly indicating a prefibrillar secretion product of the fibroblasts. b) The collagen fibrils revealed a defective lateral aggregation with disturbances of their thickness growth. Characteristic are abnormal fibrils with star-shaped cross profiles and marginal serrations in longitudinal sections. Their periodicity, however, remained normal. In three cases (Types I, I, and V) scattered giant fibrils were also present. Generally, the bundling of collagen fibrils into fibers seemed to be loosened. These findings were common to all various types of EDS. Therefore, a classification was not possible according to criteria of electron microscopy. Ehlers-Danlos syndrome is a disease of fibroblasts leading to changes of dermal collagen.