Background Filaggrin is a key structural epidermal protein in terminal differentiation and formation of skin barrier. The important role of filaggrin and its effects in various cutaneous and noncutaneous disorders initiated a cascade of considerable research in recent years. Loss‐of‐function mutations in FLG, the human gene encoding profilaggrin/filaggrin, is the cause of the common skin condition ichthyosis vulgaris (IV) and major genetic predisposing factor for atopic dermatitis (AD). Several null mutations in the FLG gene that lead to a decrease or absence of filaggrin in skin and predispose these conditions have been described. Objective The aim of this study was to investigative genetic polymorphism of FLG in Iranian patients with IV and AD. Methods In the current study, we carried out full sequencing of the entire FLG coding region in 30 IV patients and 30 AD patients, and also 60 healthy controls. Results In our research, we identified 43 variants reported previously and two novel variants. Conclusion In our study, in the AD and IV patients, loss‐of‐function FLG mutation was not found. This means that another mechanism other than FLG nonsense mutation is involved in the pathogenesis of these patients.

Background: Filament aggregating protein (Filaggrin) is a skeletal cell component that provides a protective function for the epidermis. Mutations of the filaggrin gene (FLG) cause a loss of filaggrin protein. These mutations are seen in 50% of atopic dermatitis (AD). The aim of the study was to investigate the polymorphisms and mutations of the FLG in Iranian childrenwith AD.Materials and methods: This project was a case-controlled study with 25 children diagnosed with AD as the case group and 25 healthy children as the control group. Demographic data, clinical manifestations, and filaggrin single nucleotide polymorphisms (SNPs) and mutations were recorded. Blood samples were collected for the immunoglobulin E (IgE) assay and complete blood count tests.Results: We found a significant association between the presence of polymorphism (rs66831674) and patients’ age, and polymorphism (rs41267154) and early onset of AD. We found no significant differences between the FLG polymorphisms with respect to the severity of AD, ethnicity, concurrent allergic diseases, eosinophilia, and IgE serum levels.Conclusion: Interestingly, FLG variants (rs66831674 and rs41267154) were associated with age and early onset of AD. However, additional studies are required to confirm these results on a large scale of Iranian population. Moreover, establishing a cohort prospective study is suggested to assess the progression of other atopic disorders based on FLG polymorphisms.