Identification Of A Novel Locus For Progressive Symmetric Erythrokeratodermia

IntroductionThe term erythrokeratoderma (EKs) means a heterogeneous group of disorders characterized by the mixture of erythematous and hyperkeratotic lesions by dissimilar mode; two major clinical subtypes have been described as erythrokeratodermia variabilis and progressive symmetric erythrokeratodermias which firstly reported by Mendes da Costa and Darier in 1925 and 1911, respectively. Both of them are autosomal dominant diseases with incomplete penetrance and variable expression. PSEK is characterized by fixed erythematous keratotic plaques distributing symmetrically over the body, particularly on the extremities, the buttocks, and the faces, sometimes together with palmoplantar keratoderma. The lesions of PSEK patienrs predominantly appeared in birth, infancy or childhood. The histological features of PSEK include hyperkeratosis, parakeratosis and perivascular infiltrate mainly by lymphocyte in the papillary dermis.The pathologic mechanism of PSEK is still unknown. No loci for PSEK have been defined by genetic linkage analysis up to date. Ishida-Yamamoto have acomplished serial study on PSEK, and a frameshift mutation (709insC) in the loricrin gene on chromosome 1q21 has been identified in a Japanese PSEK family with generalized, well-demarcated erythematous hyperkeratotic plaques and mutilating palmoplantar keratoderma (pseudoainhum), then published the loricrin gene as the disease gene for PSEK. Some authors considered the Japanese pedigree mentioned above affecting variant form of Vohwinkel's syndrome rather than PSEK, because pseudoainhum was usually not seen in PSEK, and the location of above mutation was only 21 bp upstream to that of Vohwinkel's syndrome variant form(730insG). We have reviewed some clinical reports of Chinese pedigrees with PSEK and analysis their clinical features and...