This theory is proven in patients with junctional epidermolysis bullosa (JEB), a disorder characterized by mutations in the COL17A1 gene resulting in the absence of collagen XVII or expression of a structurally altered protein leading to subepidermal blistering and immature HDs (44, 46–48). This evidence concerns the gene COL17A1 and Junctional epidermolysis bullosa, Herlitz type.