Association of estrogen and aromatase gene polymorphisms with systemic lupus erythematosus.

Experimental and animal studies suggested that estrogens play an important role in the development of systemic lupus erythematosus (SLE) through a variety of mechanisms involved in the regulation of the immune system. The objective of this study was to investigate the association between genetic variations in estrogen metabolic pathway genes, including estrogen receptor alpha (ESR1), estrogen receptor beta (ESR2), and aromatase (CYP19A1), and risk of SLE. We performed a genetic study of SLE among 46 medical record-confirmed female SLE cases and 102 female controls participating in an Internet-based case-control study of SLE. Polymorphisms analysed included: ESR1 PvuII, XbaI, and GT repeat; ESR2 RsaI, AluI, and CA repeat; and CYP19A1 RsaI, SfaN1, and TTTA repeat. We found significant association of the ESR1 PvuII (PP vs. pp, odds ratio (OR): 3.1, 95% confidence interval (CI): 1.1-9.3) and XbaI (XX vs. xx, adjusted OR: 3.4, 95% CI: 1.1-10.5) with SLE. Carrying the PPXX genotype conferred the highest risk (PPXX vs. ppxx, OR: 4.6, 95% CI: 1.3-15.9). We also found an association of SLE with the ESR2 CA repeat (SS vs. LL, OR: 2.8, 95% CI: 1.0-8.0). Our results support a role of estrogen in pathogenesis of SLE and suggested that genetic variants in the estrogen receptor genes might influence susceptibility.