Analysis of Taiwanese ichthyosis vulgaris families further demonstrates differences in FLG mutations between European and Asian populations

Summary Background  Mutations in the gene encoding filaggrin (FLG) were identified to underlie ichthyosis vulgaris (IV) and also shown to predispose to atopic eczema. Until now, no FLG mutations have been described in the Taiwanese population. Objectives  To elucidate filaggrin mutations in the Taiwanese population and further to clarify the population genetics of filaggrin gene mutations in the Asian populations. Methods  In the present study, 12 individuals from four unrelated Taiwanese IV families were examined for FLG mutations. We carried out comprehensive sequencing of the entire FLG coding region using an overlapping polymerase chain reaction strategy. Results  We identified three FLG mutations in the Taiwanese IV families. One mutation E1795X was a previously unidentified FLG mutation, which might be specific to the Taiwanese. Interestingly, another FLG mutation 3321delA is prevalent in the Japanese population and the other mutation Q2417X was found in the Singaporean Chinese population. No FLG mutation identified in the white European population was found in the Taiwanese population. Conclusions  The present findings suggest that the Taiwanese population, as an East Asian group, share FLG mutations with both the Japanese and the Singaporean Chinese population. In addition, these results exemplify differences in the population genetics of filaggrin between Europe and Asia.