Histopathological aid at the diagnosis of the Ehlers-Danlos syndrome, gravis and mitis types.

The Ehlers-Danlos syndrome is commonly divided into at least 8 types according to clinical, genetic, and biochemical aspects. We propose histological criteria that would permit a more precise diagnosis of the gravis and mitis types. In the gravis type, collagen bundles are thin and rare in the dermis and hypodermal septae; in polarized light, they are less refringent than in normal skin. This is associated with an increase in the relative proportion of elastic fibers. In the mitis type, the looseness of the collagen network is much less evident; elastic fibers are not in excess but irregular in size, shape, distribution, and orientation.