Lichen sclerosus (LS) is a chronic, inflammatory, mucocutaneous disorder of genital and extragenital skin. LS is a debilitating disease, causing itch, pain, dysuria and restriction of micturition, dyspareunia, and significant sexual dysfunction in women and men. Many findings obtained in recent years point more and more towards an autoimmune-induced disease in genetically predisposed patients and further away from an important impact of hormonal factors. Preceding infections may play a provocative part. The role for Borrelia is still controversial. Trauma and an occlusive moist environment may act as precipitating factors. Potent and ultrapotent topical corticosteroids still head the therapeutic armamentarium. Topical calcineurin inhibitors are discussed as alternatives in the treatment of LS in patients who have failed therapy with ultrapotent corticosteroids, or who have a contraindication for the use of corticosteroids. Topical and systemic retinoids may be useful in selected cases. Phototherapy for extragenital LS and photodynamic therapy for genital LS may be therapeutic options in rare cases refractory to the already mentioned treatment. Surgery is restricted to scarring processes leading to functional impairment. In men, circumcision is effective in the majority of cases, but recurrences are well described. Anogenital LS is associated with an increased risk for squamous cell carcinoma of the vulva or penis. This review updates the epidemiology, clinical presentation, histopathology, pathogenesis, and management of LS of the female and male genitals and extragenital LS in adults and children.

BP showed a mean incidence of 12.1 new cases per million people per year. Its incidence increased significantly after the age of 70 years, with a maximal value after the age of 90 years. The female/male ratio was 1.3. The age-standardized incidence of BP using the European population as reference was, however, lower, with 6.8 new cases per million people per year, reflecting the ageing of the Swiss population. In contrast, both PV and PF were less frequent. Their combined mean incidence was 0.6 new cases per million people per year. CONCLUSIONS; This is the first comprehensive prospective study analysing the incidence of autoimmune bullous diseases in an entire country. Our patient cohort is large enough to establish BP as the most frequent autoimmune bullous disease. Its incidence rate appears higher compared with other previous studies, most likely because of the demographic characteristics of the Swiss population. Nevertheless, based on its potentially misleading presentations, it is possible that the real incidence rate of BP is still underestimated. Based on its significant incidence in the elderly population, BP should deserve more public health concern.

Humans lacking sclerostin display progressive bone overgrowth due to increased bone formation. Although it is well established that sclerostin is an osteocyte-secreted bone formation inhibitor, the underlying molecular mechanisms are not fully elucidated. We identified in tandem affinity purification proteomics screens LRP4 (low density lipoprotein-related protein 4) as a sclerostin interaction partner. Biochemical assays with recombinant proteins confirmed that sclerostin LRP4 interaction is direct. Interestingly, in vitro overexpression and RNAi-mediated knockdown experiments revealed that LRP4 specifically facilitates the previously described inhibitory action of sclerostin on Wnt1/␤-catenin signaling. We found the extracellular ␤-propeller structured domain of LRP4 to be required for this sclerostin facilitator activity. Immunohistochemistry demonstrated that LRP4 protein is present in human and rodent osteoblasts and osteocytes, both presumed target cells of sclerostin action. Silencing of LRP4 by lentivirus-mediated shRNA delivery blocked sclerostin inhibitory action on in vitro bone mineralization. Notably, we identified two mutations in LRP4 (R1170W and W1186S) in patients suffering from bone overgrowth. We found that these mutations impair LRP4 interaction with sclerostin and its concomitant sclerostin facilitator effect. Together these data indicate that the interaction of sclerostin with LRP4 is required to mediate the inhibitory function of sclerostin on bone formation, thus identifying a novel role for LRP4 in bone.

Erythrokeratodermia variabilis (EKV, OMIM 133200) is an autosomal dominant genodermatosis with considerable intra- and interfamilial variability. It has a disfiguring phenotype characterized by the independent occurrence of two morphologic features: transient figurate red patches and localized or generalized hyperkeratosis. Both features can be triggered by external factors such as trauma to the skin. After initial linkage to the RH locus on 1p, EKV was mapped to an interval of 2.6 cM on 1p34-p35, and a candidate gene (GJA4) encoding the gap junction protein alpha-4 (connexin 31, Cx31) was excluded by sequence analysis. Evidence in mouse suggesting that the EKV region harbours a cluster of epidermally expressed connexin genes led us to characterize the human homologues of GJB3 (encoding Cx31) and GJB5 (encoding Cx31.1). GJB3, GJB5 and GJA4 were localized to a 1.1-Mb YAC in the candidate interval. We detected heterozygous missense mutations in GJB3 in four EKV families leading to substitution of a conserved glycine by charged residues (G12R and G12D), or change of a cysteine (C86S). These mutations are predicted to interfere with normal Cx31 structure and function, possibly due to a dominant inhibitory effect. Our results implicate Cx31 in the pathogenesis of EKV, and provide evidence that intercellular communication mediated by Cx31 is crucial for epidermal differentiation and response to external factors.

Angiokeratomas are vascular lesions which are defined histologically as one or more dilated blood vessel(s) lying directly subepidermal and showing an epidermal proliferative reaction. At the center of pathogenesis there is a capillary ectasia in the papillary dermis. The epidermal changes in all forms of angioker-atoma are secondary. The different entities causing vessel ectasia lead to the many clinical variants of angiokeratoma. Current classification distinguishes between widespread forms (angiokeratoma corporis diffusum), which is usually associated with an inborn error of metabolism, and localized forms, which include solitary angiokeratoma, Fordyce’s angiokeratoma, angiokeratoma circumscriptum naeviforme and angiokeratoma of Mibelli.