Abstract: 【Abstract】 Objective To investigate the relationship between vitamin D receptor （VDR） gene polymorphisms and psoriasis vulgaris. Methods From March 2018 to February 2020， a total of 101 patients with psoriasis vulgaris were collected from Department of Dermatology and Venereology, the Second Affiliated Hospital of Hainan Medical University, and 79 healthy controls from the health examination center in this hospital. All the subjects were of Han nationality from Hainan province. Targeted capture sequencing was performed to sequence the full length of the VDR gene and its 2-kb upstream and downstream regions. Single-nucleotide polymorphism （SNP）- and haplotype-based association analyses were performed for SNPs with minor allele frequency greater than 1%. Bioinformatics methods were used to predict the impact of risk SNPs on gene functions. Results The SNP-based association analysis showed that 40 SNPs, including 29 in the intron region, 1 in the exon region and 10 in the intergenic region, conferred susceptibility to psoriasis vulgaris, with the odds ratio ranging from 0.148 （95% CI: 0.016 - 1.294） to 2.779 （95% CI: 1.260 - 6.130）, and P value ranging from < 0.001 to 0.976. Bioinformatics analysis indicated that rs2228570 in exon 2 could cause the substitution of methionine by threonine, leading to changes in gene functions. The haplotype-based association analysis showed that 10 haplotypes were protective haplotypes for psoriasis vulgaris, and their frequencies were 5.150% - 45.570% in the healthy control group and 1.110% - 33.170% in the psoriasis group, with the odds ratio ranging from 0.198 （95% CI: 0.040 - 0.985） to 0.630 （95%CI: 0.419 - 0.947）, and the P value ranging from 0.002 to 0.048. Conclusion Among the Han population in Hainan Province, 40 risk SNPs for psoriasis vulgaris were identified in intron, exon and intergenic regions of the VDR gene, and 10 protective haplotypes were identified as well.

Key words: Psoriasis, Receptors, calcitriol, Polymorphism, single nucleotide, Haplotypes, Case-control studies, Targeted capture sequencing