Epidermolysis bullosa (EB) is classified into major types -EB simplex (EBS), junctional EB (JEB) and dystrophic EB (DEB) -on the basis of the level of tissue separation within the cutaneous basement membrane zone. Recent advances in research on EB have led to the identification of 10 genes responsible for EB. The Japanese Ministry of Health, Labor and Welfare has designated JEB and DEB, but not EBS, as specified diseases. However, EBS has a lethal variant and should also be registered as a specified disease. In the Third Consensus Meeting on the Diagnosis and Classification of EB held in Vienna in 2007, it was recommended that Kindler syndrome should be classified as a subtype of EB. Corrective gene therapy is the most ideal therapy for EB, but much more research is required before it can be developed and used in clinical practice. Cell-based therapies using fibroblasts and bone marrow cells have recently attracted considerable attention.

Zinc deficiency can be an inherited disorder, in which case it is known as acrodermatitis enteropathica (AE), or an acquired disorder caused by low dietary intake of zinc. Even though zinc deficiency diminishes cellular and humoral immunity, patients develop immunostimulating skin inflammation. Here, we have demonstrated that despite diminished allergic contact dermatitis in mice fed a zinc-deficient (ZD) diet, irritant contact dermatitis (ICD) in these mice was more severe and prolonged than that in controls. Further, histological examination of ICD lesions in ZD mice revealed subcorneal vacuolization and epidermal pallor, histological features of AE. Consistent with the fact that ATP release from chemically injured keratinocytes serves as a causative mediator of ICD, we found that the severe ICD response in ZD mice was attenuated by local injection of soluble nucleoside triphosphate diphosphohydrolase. In addition, skin tissue from ZD mice with ICD showed increased levels of ATP, as did cultured wild-type keratinocytes treated with chemical irritants and the zinc-chelating reagent TPEN. Interestingly, numbers of epidermal Langerhans cells (LCs), which play a protective role against ATP-mediated inflammatory signals, were decreased in ZD mice as well as samples from ZD patients. These findings suggest that upon exposure to irritants, aberrant ATP release from keratinocytes and impaired LC-dependent hydrolysis of nucleotides may be important in the pathogenesis of AE.

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Eradication of H. pylori would be a valid choice for patients with CIU, although the prevalence of H. pylori infection is not higher in patients with CIU than it is in controls.

The Papillon-Lefèvre syndrome, inherited in an autosomal recessive pattern, manifests with palmoplantar keratoderma and early, destructive periodontitis. Recently, mutations in the gene encoding cathepsin C have been disclosed in a limited number of families with Papillon-Lefèvre syndrome. We have examined two multiplex families with Papillon-Lefèvre syndrome, and evaluated the gene encoding cathepsin C for mutations. The mutation detection strategy consisted of polymerase chain reaction amplification of all seven exons and flanking intronic sequences, followed by direct nucleotide sequencing. This strategy identified two missense mutations, W39S and G301S, affecting highly conserved amino acid residues within the cathepsin C polypeptide. The affected individuals were homozygotes whereas heterozygous carriers of the mutations were clinically unaffected, confirming the recessive nature of the mutations. Addition of these cathepsin C gene mutations into the expanding Papillon-Lefèvre syndrome mutation database allows further development of genotype/phenotype correlations towards understanding this severe genodermatosis.