Ultrastructural studies in epidermolysis bullosa heriditaria. I. Dominant dystrophic type of Pasini.

Ultrastructural examination was performed in 8 biopsies from 4 patients with the Pasini type of epidermolysis bullosa dystrophica dominans. The biopsies were taken from: 1. clinically normal skin from nonpredilection areas, 2. intact skin from predilection areas, 3. involved skin and 4. experimentally frictioned skin. The main ultrastructural alterations detected are as follows: hypoplasia of anchoring fibrils, split or blister formation between basal lamina and dermis, hernia-like protrusion of basal cells, sub- and intraepidermal deposition of fibrillar bodies, and duplications of basal lamina. Among them, the constantly observed finding in all of the four biopsy groups in the structural defect of anchoring fibrils, namely, that the anchoring fibrils are rudimentary and reduced in number. Presence of the structural defect of anchoring fibrils in clinically normal skin from nonpredilection areas in patients with the Pasini type of epidermolysis bullosa dystrophica dominans indicates that this defect is not a secondary change following repeated mechanical trauma, but a primary, genetically determined event.