Association between polymorphisms and atopic dermatitis susceptibility: A systematic review and meta-analysis

AIM

Atopic dermatitis (AD) is a chronic pruritic inflammatory skin disease that is closely linked to genetic factors. Previous studies have revealed numerous single nucleotide polymorphisms (SNPs) that been related to susceptibility to AD; however, the results are conflicting. Therefore, a meta-analysis was conducted to assess the associations of these polymorphisms and AD risk.

MATERIAL AND METHODS

PubMed, Web of Science, Embase, Cochrane Library, and China National Knowledge Infrastructure databases were retrieved to identify eligible studies, with selected polymorphisms being reported in a minimum of three separate studies. The Newcastle-Ottawa Scale (NOS) was used to evaluate study quality. Review Manager 5.3 and STATA 14.0 were used to perform the meta-analysis.

RESULTS

After screening, 64 studies involving 13 genes (24 SNPs) were selected for inclusion in the meta-analysis. Nine SNPs were positively correlated with AD susceptibility [filaggrin (FLG) R501X, FLG 2282del4, chromosome 11q13.5 rs7927894, interleukin (IL)-17A rs2275913, IL-18 -137 G/C, Toll-like receptor 2 (TLR2) rs5743708, TLR2 A-16934 T, serine protease inhibitor Kazal type-5 (SPINK5) Asn368Ser, interferon-γ (IFN-γ) T874A] and one was negatively associated with AD susceptibility (IL-4 -1098 T/G). The 14 remaining SNPs were not significantly associated with AD susceptibility.

CONCLUSIONS

Nine SNPs that may be risk factors and one SNP that may be a protective factor for AD were identified, providing a reference for AD prediction, prevention, and therapy.

Candidate Gene Association Studies in Atopic Dermatitis in Participants of European and Asian Ancestry: A Systematic Review and Meta-Analysis

Atopic dermatitis (AD) has been extensively investigated for genetic associations utilizing both candidate gene approaches and genome-wide scans. Here, we comprehensively evaluated the available literature to determine the association of candidate genes in AD to gain additional insight into the etiopathogenesis of the disease. We systematically screened all studies that explored the association between polymorphisms and AD risks in cases of European and Asian ancestry and synthesized the available evidence through a random-effects meta-analysis. We identified 99 studies that met our inclusion/exclusion criteria that examined 17 candidate loci in Europeans and 14 candidate genes in Asians. We confirmed the significant associations between FLG variants in both European and Asian populations and AD risk, while synthesis of the available data revealed novel loci mapped to IL18 and TGFB1 genes in Europeans and IL12RB1 and MIF in Asians that have not yet been identified by genome-wide association studies. Our findings provide comprehensive evidence for AD risk loci in cases of both European and Asian ancestries, validating previous associations as well as revealing novel loci that could imply previously unexplored biological pathways.

Genetic relationship between IL-10 gene polymorphisms and the risk of clinical atopic dermatitis

Background

We retrieved different reports containing different genetic effects of − 1082 A/G, − 819 T/C, and − 592 A/C polymorphisms within the IL-10 (interleukin-10) gene on the susceptibility to clinical atopic dermatitis.

Methods

Herein, we conducted a meta-analysis to comprehensively assess such a genetic relationship after collecting the available published evidence. STATA 12.0 software was used for the statistical analysis under the allelic, homozygotic, heterozygotic, dominant, recessive and carrier genetic models.

Results

By retrieving and screening database literature, a total of 16 eligible case-control studies were finally selected. For the IL-10 -1082 A/G polymorphism, we did not detect a significant difference between atopic dermatitis cases and population-based controls in the overall meta-analysis under the genetic models of allele G vs. A (P = 0.540), GG vs. AA (P = 0.853), AG vs AA (P = 0.265), AG + GG vs AA (P = 0.221), GG vs AA+AG (P = 0.540) and carrier G vs. A (P = 0.643). Moreover, a statistically non-significant association was observed in the most subgroup meta-analyses by the factors of ethnicity, country and Hardy-Weinberg equilibrium. Likewise, the negative results were detected for the synthetic analysis of IL-10 -819 T/C and − 592 C/A polymorphisms.

Conclusion

The current evidence does not support a strong genetic relationship between IL-10 -1082 A/G, − 819 T/C and − 592 A/C polymorphisms and the susceptibility to atopic dermatitis.

Electronic supplementary material

The online version of this article (10.1186/s12881-019-0817-8) contains supplementary material, which is available to authorized users.

Genetic polymorphisms and the development of invasive bacterial infections in children

To evaluate the associations between single nucleotide polymorphisms (SNPs) of factors involved in the development of invasive bacterial disease (IBD) in children, 47 SNPs of 18 candidate genes were analysed in 49 children with IBD and 100 controls. The G/T genotype of TLR2 rs2149356 and the C genotype of LTA rs2229094 were associated with significantly reduced risk of developing IBD (P=0.04 and P=0.05, respectively), whereas the C/T genotype of RFP175 rs1585110 was associated with a significantly higher risk of developing IBD (P=0.02). These results support the evidence that some genetic variants of factors involved in innate immunity may influence IBD risk in children.