ABSTRACT
Objective To investigate the association between endoplasmic reticulum aminopeptidase 1 (ERAP1)gene polymorphisms and psoriasis vulgaris (PsV)in a Chinese Han population. Methods Five milliliters of venous blood samples were collected from 289 patients with PsV and 292 human controls of Han nationality after informed consent. Three single nucleotide polymorphisms (SNPs)in the encoding area of the ERAP1 gene, including rs27044, rs30187 and rs26653, were genotyped by ligase detection reaction (LDR). With the PLINK 1.07 package, statistical analysis was carried out by using the chi-square test for comparisons of allele and genotype frequencies between the patient group and control group. The allelic odds ratio (OR)and its 95% confidence interval (CI)were calculated. In addition, haplotype analysis was conducted with the Haploview software. Results The frequencies of rs30187-C and rs26653-G alleles were significantly lower in the patient group (0.460 2 and 0.430 8 respectively), especially in patients with early-onset PsV(0.448 5 and 0.422 7 respectively), than in the control group(0.534 2 and 0.501 7 respectively, all P <0.05). The SNPs rs27044, rs30187 and rs26653 showed strong linkage disequilibrium with each other (r2 ≥ 0.717, D′ ≥0.962). Genotype analysis showed that the frequency of the rs30187 CC genotype was significantly lower in the patient group, especially in patients with early-onset PsV, than in the control group (P < 0.05 and 0.016 7 respectively)under a recessive mode of inheritance. Haplotype analysis revealed that the frequency of the haplotype H4: CTC was significantly increased in the patient group(0.050), especially in patients with early-onset PsV(0.052), compared with the control group (0.022, P < 0.05 and 0.016 7 respectively). Conclusions ERAP1 gene polymorphisms are associated with PsV, especially with early-onset PsV in Chinese Han population. The risk haplotype H4: CTC may be a susceptible factor for PsV.