Apolipoprotein E Gene Polymorphism in Psoriasis: A Meta-analysis

Background and Aims. Several studies have shown that the apolipoprotein E (ApoE) gene is associated with the development of psoriasis. However, there is a controversy. The aim of the present study was to evaluate the association of psoriasis risk with ApoE polymorphisms. Methods. We carried out a systematic search of studies that explored associations between ApoE polymorphisms and psoriasis. The genotype distribution of the control group in each study was calculated to determine whether or not there was compliance with the Hardy-Weinberg equilibrium. Overall effect sizes were assessed by odds ratio (OR) with 95% confidence intervals (CI). The selection to use the random-effects model or fixed-effects model depended on the size of the heterogeneity among the included studies. The fail-safe number (Nfs) was used to test the potential publication bias. We analyzed the data using Stata v.10.0. Results. A total of seven studies with 966 patients and 1,086 controls were included. The results indicated that the epsilon 2 allele was associated with increased risk of psoriasis (epsilon 2 vs. epsilon 3+epsilon 4: OR = 1.47, 95% CI = 1.23-1.75, p < 0.05), whereas the epsilon 3 allele and epsilon 3/epsilon 3 genotype may decrease risk of psoriasis (OR = 0.71, 95% CI = 0.62-0.82, p < 0.05; OR = 0.63, 95% CI = 0.52-0.77, p < 0.05, respectively). In the subgroup analysis according to ethnicity, the increased risk of psoriasis remained in the Asian and European populations, whereas no significant association was found in other populations for other polymorphisms. Conclusions. Our study suggests that the ApoE polymorphisms are associated with the risk of psoriasis, especially epsilon 2 and epsilon 3 alleles. Further studies are needed to confirm our results. (C) 2013 IMSS. Published by Elsevier Inc.