Altered secretion of type III procollagen in a form of type IV Ehlers-Danlos syndrome. Biochemical studies in cultured fibroblasts.

Cultured dermal fibroblasts from a woman with one variety of type IV Ehlers-Danlos syndrome synthesized type III procollagen but fail to secrete the bulk of the protein. Although total collagen production is similar to that of controls, the affected cells retain almost twice as much collagen as controls. The additional retained protein is a disulfide-boned collagenous trimer that remains disulfide-linked after limited proteolysis with pepsin and, after pepsin treatment, migrates with type III collagen on polyacrylamide gel electrophoresis. Affected cells have markedly increased staining with antibodies directed against type III procollagen. These studies indicate that decreased secretion of type III procollagen that is synthesized can result in the clinical syndrome of type IV Ehlers-Danlos syndrome.