Association of the oestrogen receptor α gene polymorphisms with disease onset in systematic lupus erythematosus

Objective: To evaluate the genetic influence of Pbull and Xbal polymorphisms of oestrogen receptor α (ORα) in patients with systemic lupus erythematosus (SLE) in Korea. Methods: Genomic DNA from 268 female controls and 137 female SLE patients (41 childhood onset and 96 adult onset) were analysed using Pvull and Xbal restriction fragment length polymorphism. Comparison of the frequencies of alleles and genotypes was made in control and patient groups and in childhood onset and adult onset SLE subgroups. Results: Although the Pp genotype occurred more often in SLE patients than in controls (p_c = 0.017), ORα genotype distributions of adult onset SLE did not differ significantly from controls. The PP, Pp, and xx genotypes occurred less often in childhood onset SLE (p_c = 0.0045, 0.0498, and 0.0255, respectively) than in controls. Additionally, the PP genotype was less common in childhood onset than in adult onset SLE (p _c = 0.016). SLE patients with the PP genotypes were older at disease onset than those with the other genotypes (p = 0.001). Patients with the Xx genotype had an earlier onset of SLE than those with the xx genotype (p = 0.025). The frequency of the combined ppXx genotype was greater in childhood onset SLE than in controls (p_c = 0.0009) or adult onset SLE (p _c = 0.027). The same trend was supported by subgroup analyses according to age at menarche and logistic multivariate analyses. Conclusions: ORα polymorphisms are significantly associated with the age at disease onset in Koreans with SLE.