Generalized atrophic benign epidermolysis bullosa: a case of severe hemidesmosomal deficiency.

A case of generalized atrophic benign epidermolysis bullosa was followed from birth to 14 years of age. Electron microscopy of the blistered skin showed either the absence or greatly reduced hemidesmosomes of a very poorly developed type. In perilesional skin, the frequency of hemidesmosomes was 1/3 to 1/2 of the normal controls. These hemidesmosomes were small and lacked normal ultrastructures. Anchoring filaments did not cluster underneath them, and the anchoring fibrils were also diminished. In view of the published data correlating the genotype to the phenotype, this patient seems to have a homozygous nonsense mutation of the COL17A1 gene encoding collagen XVII. An accumulation of data may eventually enable electron microscopists to estimate the types of gene mutation.