Association of vitamin D receptor gene FokI polymorphism with systemic lupus erythematosus / 中华风湿病学杂志

ABSTRACT

Objective To determine the distribution of vitamin D receptor(VDR)gene FokI polymorphism in systemic lupus erythematosus(SLE)and the association with SLE in Chinese Han patients. Methods Genomic DNA from 271 Chinese SLE patients and 130 sex and ethnically matched controls were typed for VDR FokI polymorphism by polymerase chain reaction restriction fragment length polymorphism(PCRRFLP). Clinical characteristics were analyzed between different FokI genotypes. ResuIts Fokl allelic frequencies were not in Hardy-Weinberg equilibrium(χ2=7.288, P=0.026 for the control group and χ2=7.883, P=0.019 for the SLE patient group). The distribution frequencies of allelic gene F and f were 48.8% and 51.2% in the controls respectively, 60.9% and 39.1%(χ2=10.39, P=0.001)in the SLE patients respectively. The relative risk of allelic gene F developing to SLE was 1.630(95%CI=1.210～1.196, χ2=10.39, P=0.001). The distribution frequencies of genotypes homozygote FF, heterozygote Ff and homozygote ff were 25.4%, 46.9%,and 27.7% in the controls respectively; 42.8%(χ2=11.417, P=0.001), 36.2%(χ2=4.251, P=0.039)and 21.0% (χ2=2.187, P=0.139)in SLE respectively. The relative risk of homozygote FF and heterozygote Ff genotypes was 2.200(95%CI=1.385～3.493, χ2=11.417, P=0.001)and 0.641(95%CI=0.419～0.979, χ2=4.251, P=0.039)respectively. Furthermore, no significant difference was observed in SLE patients carrying different FokI genotypes in SLE disease activity index(SLEDAI)(P=0.382), symptoms and signs, while significant difference was observed in SLE patients carrying heterozygote Ff genotypes involved in serositis(P=0.001). Elevated frequencies of heterozygote Ff genotypes were observed in patients with anti-dsDNA antibody, anti-Sm antibody and anti-histone antibody respectively(P=0.001, P=0.047, P=0.001 respectively). However, the incidence rate of malar rash was lower than other genotypes in heterozygote Ff genotypes(P=0.005).Conclusion There is association between the VDR gene FokI polymorphism and the susceptibility to systemic lupus erythematosus in Han population of southern China. Allelic gene F, homozygote FF and heterozygote Ff genotypes increase the susceptibility to systemic lupus erythematosus. Otherwise, heterozygote Ff genotype is more frequently involved in serositis and generates anfi-dsDNA antibody, anti-Sm antibody and anti-Histone antibody.