The 2019 European League Against Rheumatism/American College EULAR/ACR classification criteria for SLE include the presence of positive antinuclear antibody (ANA) at least once as obligatory entry criterion, followed by additive weighted criteria grouped in seven clinical (constitutional, hematologic, neuropsychiatric, mucocutaneous, serosal, musculoskeletal, renal) and three immunological (antiphospholipid antibodies, complement proteins, SLE-specific antibodies) domains, and weighted from 2 to 10. This evidence concerns the gene BTG3 and systemic lupus erythematosus.