Association analysis of filaggrin gene mutations and atopic dermatitis in Northern China

Conflicts of interest: none declared. L.M. and L.Z. contributed equally to this work. Madam, Atopic dermatitis (AD) is a multifactorial disease, which arises from the interaction between strong genetic and environmental factors.1 Recently, there has been growing evidence that heritable skin barrier defects caused by mutations in the filaggrin gene (FLG) play an important role in the pathogenesis of AD.2 In FLG, the nonsense mutation R501X and the frameshift mutation 2282del4 were the first mutations shown to be associated with development of AD in a caucasian population. Each mutation results in a premature stop codon of FLG leading to filaggrin deficiency and a damaged skin barrier.3 Subsequently, mutations R2447X, S3247X and 3702delG were also reported to be associated with the development of European AD.4 Although the strong association of R501X and 2282del4 mutations and development of AD has been replicated in several European populations, it was absent in non‐European populations, such as those of Asian and African origin.3 Mutations R2447X, S3247X and 3702delG were also absent in Asian patients with AD.4 In Asian population studies, the 3321delA frameshift mutation and the S2554X nonsense mutation were found to be associated with development of AD in Japanese patients,5 6–7 but the two Asian mutations were not found in European patients with AD.4FLG mutations may have regional and ethnic differences.