Two polymorphisms, ESR1 PvuII T/C (rs2234693) and ESR1 XbaI A/G (rs9340799), located in the first intron of the ESR1 gene, have been extensively studied, but the associations between these polymorphisms and SLE susceptibility remain controversial [19], [20]. The gene discussed is ESR1; the disease is systemic lupus erythematosus.