Loss-of-Function Mutations in the Gene Encoding Filaggrin Are Not Strongly Associated with Chronic Actinic Dermatitis.
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ABSTRACT:
SUBMITTER: Harkins CP
PROVIDER: S-EPMC7116004 | biostudies-literature | 2015 Jul
REPOSITORIES: biostudies-literature
Publications
Loss-of-Function Mutations in the Gene Encoding Filaggrin Are Not Strongly Associated with Chronic Actinic Dermatitis.
Harkins Catriona P CP Waters Alex A Kerr Alastair A Campbell Linda L Irwin McLean W H WH Brown Sara J SJ Ibbotson Sally H SH
The Journal of investigative dermatology 20150303 7
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Project description:Atopic dermatitis is frequently associated with the onset of other allergic conditions, such as asthma, rhino-conjunctivitis and food allergy. The etiology of atopic dermatitis is marginally understood in spite of the number of predisposing factors, above all, mutations in the Filaggrin gene (FLG). In this study, the association between loss-of-function variants in the FLG gene and other allergic manifestations, in particular food allergy, was evaluated in an Italian pediatric population affected by atopic dermatitis. The 10 more frequently mutated loci in the FLG gene were genotyped in 238 children affected by atopic dermatitis and tested for association with clinical features of allergic disorders by a multivariate logistic regression model. R501X and 2282del4 were the only two mutations identified; 12.2% of children carry one of these variants, corresponding to an allelic frequency of 6.5%. According to multivariate statistical analysis, loss-of-function variants in the FLG gene represent a risk factor for the onset of severe manifestations of food allergy (OR = 8.9; CI: 3.1-28.3). Peanut and hazelnut were identified as high-risk foods in patients with FLG mutations. This study demonstrates that atopic children carrying FLG mutations represent a high-risk population due to their predisposition to develop severe food allergy reactions, such as anaphylaxis.
| S-EPMC7827548 | biostudies-literature
Project description:Keratosis pilaris (KP) associates with epidermal barrier defects in atopic dermatitis (AD) but its role in disease severity and concomitant atopic diseases seems to vary between populations. We performed a cross-sectional observational study with 502 randomly selected AD patients of a Finnish tertiary health care center. At a single clinical examination, disease severity (Rajka Langeland severity score and EASI), clinical signs and patient history were evaluated and total IgE levels and frequent filaggrin (FLG) loss-of-function mutations were investigated. There was no link with disease severity (p = 0.649, 95% CI 0.569-0.654), asthma (p = 0.230, 95% CI 0.206-0.281) or atopic sensitization (p = 0.351, 95% CI 0.309-0.392). Keratosis pilaris was significantly associated with palmar hyperlinearity (p < 0.000, 95% CI 0.000-0.006, OR 4.664, 95% CI 2.072-10.496) and the filaggrin loss-of-function mutation 2282del4 (p < 0.000, 95% CI 0.000-0.009, OR 4.917, 95%CI 1.961-12.330). The prevalence of KP in the cohort was generally low and KP seems to be infrequent in Finnish AD patients. This may be explained by the fact that the tested FLG loss-of-function mutations are rarer in the Finnish population compared for example, with central Europe or Asia. Mutations in other locations of the FLG gene or other genes of the epidermal barrier may play a more important role.
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Project description:ImportanceAtopic dermatitis (AD) is a common chronic illness of childhood.ObjectiveTo evaluate the association between thymic stromal lymphopoietin (TSLP) variation and the persistence of skin symptoms of AD.Design, setting, and participantsA prospective cohort study was conducted in the general community. Participants included 796 children enrolled in the Pediatric Eczema Elective Registry. EXPOSURE Evaluation of TSLP variation.Main outcomes and measuresSelf-reported outcome of whether a child's skin had no symptoms of AD and required no medications for 6 months at 6-month intervals.ResultsWe evaluated 14 variants of TSLP. The variant rs1898671 was significantly associated with the outcome in white children (P = .01). As measured by overlapping CIs, similar odds ratios (ORs) were noted among whites (OR, 1.72; 95% CI, 1.11-2.66) and African Americans (1.33; 0.52-3.45). Further within the subcohort of individuals with a filaggrin protein (FLG) loss-of-function mutation, those with TSLP variation were more likely to have less-persistent disease (OR, 4.92; 95% CI, 2.04-11.86).Conclusions and relevanceThe TSLP variation is associated with less persistent AD. Therefore, TSLP may be a potential therapeutic target for the treatment of AD, especially in individuals with diminished barrier function due to FLG mutations. This is an attractive hypothesis that can be tested in clinical trials.
| S-EPMC4414492 | biostudies-literature
Project description:ImportanceAtopic dermatitis (AD) is a common chronic illness that has been associated with variation in the filaggrin gene (FLG). Four variants are most often evaluated.ObjectivesTo comprehensively describe and compare results from targeted sequencing of FLG loss-of-function (LoF) variants in children of African and European ancestry and the association of these variants with onset and persistence of AD.Design, setting, and participantsThis prospective US cohort study assessed the genetic subcohort of the Pediatric Eczema Elective Registry (PEER). Children with mild to moderate AD were included in the analysis. Massively parallel sequencing (MPS) was used to focus on FLG LoF variation in white and African American children. Patients were enrolled from June 2005 through July 2017. Data were analyzed from January 25 through May 10, 2019.Main outcomes and measuresAssociations of FLG LoF variation with white and African American ancestry and with the risk and persistence of AD.ResultsA total of 741 children were included in the analysis (394 [53.2%] female and 347 [46.8%] male; mean [SD] age at onset, 1.97 [2.72] years); of these, 394 (53.2%) were white, 326 (44.0%) were African American, and 21 (2.8%) were of other ancestries. Using MPS technology, 23 FLG LoF variants were found in children with AD. The prevalence of FLG LoF variants was 177 participants (23.9%) in the full cohort, 124 white participants (31.5%), and 50 African American participants (15.3%). The odds ratio for carrying any FLG LoF variant in a white child compared with an African American child with AD was 2.44 (95% CI, 1.76-3.39). Some FLG LoF variants are only found in children of a specific ancestry (eg, p.S3316* and p.R826* were not seen in white patients). Children with an FLG LoF were more likely to have persistent AD (odds ratio, 0.67; 95% CI, 0.56-0.80).Conclusions and relevanceThe FLG LoF variants in a US cohort of children with mild to moderate AD differ significantly by race and their association with the persistence of AD. Conventional testing of the 4 frequently evaluated variants is inadequate. Any planned genetic diagnostic test for AD based on FLG LoF variants must be inclusive and not rely on the most frequently studied variants.
| S-EPMC6669787 | biostudies-literature
Project description:The genetic background of Atopic Dermatitis (AD) with chronic pruritus is complex. Filaggrin (FLG) is an essential gene in the epidermal barrier formation s. Loss-of-function (LOF) variants in FLG associated with skin barrier dysfunction constitute the most well-known genetic risk factor for AD. In this study, we focused on the frequency and effect of FLG loss-of-function variants in association with self-reported age-of-onset of AD. The dataset consisted of 386 whole-genome sequencing (WGS) samples. We observe a significant association between FLG LOF status and age-of-onset, with earlier age of onset of AD observed in the FLG LOF carrier group (p-value 0.0003, Wilcoxon two-sample test). We first tested this on the two most prevalent FLG variants. Interestingly, the effect is even stronger when considering all detected FLG LOF variants. Having two or more FLG LOF variants associates with the onset of AD at 2 years of age. In this study, we have shown enrichment of rare variants in the EDC region in cases compared with controls. Age-of-onset analysis shows not only the effect of the FLG and likely EDC variants in terms of the heightened risk of AD, but foremost enables to predict early-onset, lending further credence to the penetrance and causative effect of the identified variants. Understanding the genetic background and risk of early-onset is suggestive of skin barrier dysfunction etiology of AD with chronic pruritus.
| S-EPMC7026049 | biostudies-literature
Project description:Filaggrin, encoded by the FLG gene, plays a crucial role in the barrier function of epidermis, but the association between FLG loss-of-function mutations and infectious skin diseases has not been systematically studied. FLG coding sequences from 945 patients with leprosy and 916 healthy controls were captured and enriched using an array-based high-throughput system, and subjected to next-generation sequencing. The loss-of-function mutations found were further validated by Sanger sequencing. A total of 21 loss-of-function mutations were found in 945 patients with leprosy, with a carrier rate of 17.53%, while the prevalence of these mutations in 916 healthy controls was 14.77%, which was significantly lower than in patients. Two individual FLG loss-of-function mutations (K4022X and Q1790X) were found to be significantly associated with leprosy. These results suggest a possible role for filaggrin in defending against leprosy pathogens.
| S-EPMC9274930 | biostudies-literature
Project description:ImportanceSkin microbiome correlates with disease severity for lesional and nonlesional skin, indicating a global influence of atopic dermatitis (AD). A relation between skin microbiome and filaggrin gene (FLG) mutations proposes a possible association between skin microbiome and host genetics.ObjectivesTo assess skin and nasal microbiome diversity and composition in patients with AD and compare with healthy controls, and to investigate the microbiome in relation to disease severity and FLG mutations in patients with AD.Design, setting, and participantsAn observational case-control study of 45 adult healthy controls and 56 adult patients with AD was carried out from January 2015 to June 2015 in a tertiary referral center, Department of Dermatology, Bispebjerg Hospital, Denmark.ExposuresBacterial swabs were taken from patients with AD (lesional skin, nonlesional skin, and anterior nares) and from healthy controls (nonlesional skin and anterior nares). Eczema severity was assessed and FLG mutations noted. Bacterial DNA was extracted from swabs, and V3-V4 16S rDNA regions amplified with PCR. Samples were analyzed at Statens Serum Institut September 2015 to September 2016. Bioinformatics analyses of the microbiome were analyzed using R statistical software (version 3.3.1, R Foundation Inc).Main outcomes and measuresSkin microbiomes were investigated using next-generation sequencing targeting 16S ribosomal RNA.ResultsMicrobiome alpha diversity was lower in patients with AD compared with healthy controls in nonlesional skin (effect size, 0.710; 95% CI, 0.27-1.15; P = .002), lesional skin (effect size, 0.728; 95% CI, 0.35-1.33; P = .001), and nose (effect size, 1.111; 95% CI, 0.48-0.94; P < .001). Alpha diversity was inversely correlated with disease severity for lesional (effect size, 0.530; 95% CI, 0.23-1.64; P = .02) and nonlesional skin (effect size, 0.451; 95% CI, 0.04-2.44; P = .04) in patients with AD. Microbiome composition in AD nonlesional skin was linked to FLG mutations.Conclusions and relevanceAn altered microbiome composition in patients with AD in nonlesional skin, lesional skin, as well as nose, suggests a global influence of AD. Microbiome composition in AD nonlesional skin is associated with FLG mutations, proposing a possible association between the skin microbiome and host genetics.
| S-EPMC5885821 | biostudies-literature
Project description:BackgroundInteractions between the skin barrier, immune system, and microbiome underlie the development of atopic dermatitis (AD).ObjectiveTo investigate the skin and nasal microbiome in relation to filaggrin gene (FLG) mutations.MethodsA cross-sectional study including 77 children with difficult-to-treat AD. The entire encoding region of FLG was screened for mutations using single molecule molecular inversion probes and next-generation sequencing. Bacterial swabs from the anterior nares, lesional and nonlesional skin were analyzed using 16S rRNA sequencing. For skin samples, additional qPCR was performed for Staphylococcus aureus and Staphylococcus epidermidis.ResultsThe prevalence of patients with a mutation in FLG was 40%, including 10 different mutations. Analyzing bacterial swabs from all three niches showed a significant effect for both niche and FLG mutation status on the overall microbiome composition. Using a subset analysis to test the effect of FLG mutation status per niche separately did not show a significant association to the microbiome. Shannon diversity and S. aureus abundance were significantly affected by the niche, but not by the presence of an FLG mutation.ConclusionsOur results suggest only a minor role for FLG mutation status on the overall microbiome, which is rather caused by differences in the present genera than by microbe richness and evenness.
| S-EPMC9501786 | biostudies-literature
Project description:BackgroundFilaggrin is an epidermal protein that has a role in skin barrier function. Filaggrin loss-of-function (FLG-LOF) mutations are a significant risk factor for eczema and atopy, but their association with food allergy (FA) is less clear.ObjectiveWe explored the longitudinal relationship between 3 common FLG-LOF mutations and FA using the Isle of Wight birth cohort.MethodsFA diagnosis was based on recognized allergic reactions within 4 hours after exposure to known food allergens. Food allergen sensitization (FAS) was identified by using skin prick tests conducted between 1 and 18 years of age to a range of food allergens. Three FLG mutations were genotyped in 1150 (79%) of 1456 children. The temporal relationships between FA, FAS, and eczema in children with FLG mutations were explored by using path analysis with total, direct, and indirect effect models.ResultsThere was a significant total effect of FLG-LOF mutations on the risk of FA in later childhood at the ages of 10 (odds ratio, 31.46; 95% CI, 2.86 to >100) and 18 (odds ratio, 4.25; 95% CI, 1.55-11.61) years. Path analysis showed that there was no direct effect of FLG-LOF mutations on FA at any age; however, an indirect effect was found on FA at all ages through eczema and FAS in the earlier years.ConclusionFLG-LOF mutations are associated with FA in older children through eczema and FAS during early childhood. Our results highlight a biologically plausible pathway, which suggests that skin barrier function is important in the development and persistence of FA.
| S-EPMC4186905 | biostudies-literature
Project description:Skin pigmentation lightened progressively to a variable extent, as modern humans emigrated out of Africa, but extreme lightening occurred only in northern Europeans. Yet, loss of pigmentation alone cannot suffice to sustain cutaneous vitamin D3 (VD3) formation at the high latitudes of northern Europe. We hypothesized that loss-of-function mutations in the epidermal structural protein, filaggrin (FLG), could have evolved to sustain adequate VD3 status. Loss of FLG results in reduced generation of trans-urocanic acid, the principal endogenous ultraviolet-B (UV-B) filter in lightly-pigmented individuals. Accordingly, we identified a higher prevalence of FLG mutations in northern European populations when compared to more southern European, Asian and African populations that correlates significantly with differences in circulating 25-OH-VD3 levels in these same populations. By allowing additional UV-B penetration and intracutaneous VD3 formation, the latitude-dependent gradient in FLG mutations, likely together with other concurrent mutations in VD3 metabolic pathways, provide a non-pigment-based mechanism that sustains higher levels of circulating VD3 in northern Europeans. At the time that FLG mutations evolved, xerosis due to FLG deficiency was a lesser price to pay for enhanced VD3 production. Yet, the increase in FLG mutations has inadvertently contributed to an epidemic of atopic diseases that has emerged in recent decades.
| S-EPMC4261051 | biostudies-literature