Filaggrin loss-of-function mutations and levels of filaggrin degradation products in adult patients with atopic dermatitis in Croatia
JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY AND VENEREOLOGY
Authors: Jurakic Toncic, R.; Kezic, S.; Jakasa, I.; Ljubojevic Hadzavdic, S.; Balic, A.; Petkovic, M.; Pavicic, B.; Zuzul, K.; Marinovic, B.
Abstract
Background FLG loss-of-function mutations (FLG LOF) represent the strongest genetic risk factor for atopic dermatitis (AD) and are associated with early-onset and more severe disease. The prevalence of FLG mutations varies greatly across Europe. At present, there are no data on FLG mutation prevalence in Croatian AD patients. Objectives To investigate the prevalence of FLG LOF mutations in adult patients with AD and healthy controls. Next to measure the stratum corneum (SC) levels of filaggrin degradation products (NMF), transepidermal water loss (TEWL) and pH in lesional and non-lesional skin. Methods We recruited 100 AD patients with moderate to severe disease and 50 healthy controls. They were screened for three FLG mutations (R501X, 2282del4 and R2447X). Samples of the SC for NMF analysis were collected by adhesive tapes. TEWL and skin surface pH levels were determined on the lesional and non-lesional skin. Results The combined mutation frequency was 4% in the AD group, and all patients with FLG mutations were homozygous carriers. In the control group, no mutations were found. The most common FLG mutation in AD patients was 2282del4 (3%), followed by R501X (1%). As compared to healthy controls, NMF values were strongly reduced in lesional skin; however, no significant difference was found for non-lesional skin. AD patients had elevated TEWL in both lesional and non-lesional skin. The same pattern was observed for pH. Conclusions Our study expands understanding of the landscape of FLG mutations in the European population. The low frequency of FLG mutations and similar levels of filaggrin degradation products in healthy controls and in non-lesional skin of AD patients suggest that filaggrin deficiency does not confer a major risk for AD in the Croatian population.
Simultaneous detection of barrier- and immune-related gene variations in patients with atopic dermatitis by reverse blot hybridization assay
CLINICAL AND EXPERIMENTAL DERMATOLOGY
Authors: Yoon, N. Y.; Wang, H. Y.; Jun, M.; Jung, M.; Kim, D. H.; Lee, N. R.; Hong, K. -W.; Seo, S. J.; Choi, E.; Lee, J.; Lee, H.; Choi, E. H.
Abstract
Background. Hereditary factors are involved in the pathogenesis of atopic dermatitis (AD). However, AD-related gene variations are significantly different across ethnicities. Aim. To identify mutations and single-nucleotide polymorphisms (SNPs) in barrieror immune-related genes from Korean patients with AD and compare the variations with those observed in nonatopic healthy controls (HCs), and to use novel reverse blot hybridization assay (REBA) for AD-related gene variants. Methods. We carried out REBA to simultaneously detect variations in genes related to barrier or immune function, namely, FLG, SPINK5, KLK7, DEFB1, TNF alpha, KDR, FCER1A, IL4, IL5, IL5RA, IL9, IL10, IL12, IL12R, IL13 and IL18, from Korean patients with AD, and compared the variation to that in nonatopic healthy controls. Results. The homozygous mutants of KLK7 and SPINK5-2475, and the heterozygous mutants of FLG 3321delA, SPINK5-1156, DEFB1, KDR, IL5RA, IL9 and IL12RB1 were significantly more frequent in AD. It has been predicted that the larger the number of gene variants, the higher the odds ratio of AD prevalence; however, we did not find any significant correlation between the number of gene variants and AD severity. Conclusion. Using REBA, we identified more genetic variants that can predict AD occurrence. We also verified that REBA can be used to easily and accurately detect multiple AD-related gene variants simultaneously. In addition, we identified a correlation between KLK7 mutation and AD in Koreans, which is the first such report, to our knowledge.