Ultrastructural studies in epidermolysis bullosa hereditaria. II. Dominant dystrophic type of Cockayne and Touraine.

Ultrastructural examination was performed in 9 biopsy specimens from 4 patients with the Cockayne-Touraine type of epidermolysis bullosa dystrophica dominans. The specimens were taken from: 1. clinically normal skin from the blister-nonpredilected sites (trunk) as well as 2. atrophic, 3. intact, and 4. experimentally frictioned skin regions from the blister-predilected sites (extremities). In the frictioned skin a dermolytic blister formations was observed. Development of anchoring fibrils showed a marked regional difference, the counts of fibrils being significantly lower (40%) in the predilection sites than in the nonpredilection sites. In addition the anchoring fibrils showed a variable degree of abnormal structure. The low frequency of often abnormally structured anchoring fibrils in the blister-preferred sites provides a good explanation for the clinical features. More studies are needed to see if regional differences in fibril frequency is a feature also of normal skin, in which case the dominant epidermolysis gene may represent a mutated structural anchoring fibril gene.