Monogenic murine models of lupus — i.e., Dnase1–/– or Dnase1L3–/– mice — faithfully reproduce the lupus phenotype present in humans, including elevated titers of autoantibodies against dsDNA, histones, and chromatin (ANAs), splenomegaly with expanded white pulp (germinal center B cells); and background-dependent glomerulonephritis, which appears in a 129 inbred mouse background (24–26). Here, DNASE1L3 is linked to systemic lupus erythematosus.