In clinical trials up to 30% of patients with an established diagnosis of SLE were found to be ANA negative at enrollment.2 This observation may be related to differences in assay performance, but, at the same time, it may be the result of other factors, such as the demographic characteristics of patients (i.e., race or age), the natural history of the disease or the effects of treatments. This evidence concerns the gene BTG3 and systemic lupus erythematosus.