The strongest evidence for association was observed outside the
MHC and included markers localized to 4q11-q13 (PDGFRA, GSX2; P54.531027), 16p12 (SLC5A11;
P55.131027), 6p22 (ID4; P57.431027), and 8q24.12 (HAS2, SNTB1; P51.131026). Both HLA-DR2 and
HLA-DR3, two well established lupus susceptibility loci, showed evidence of association with lupus nephritis (P=0.06 and P53.731025, respectively).Within the class I region, rs9263871 (C6orf15-HCG22)had
the strongest evidence of association with lupus nephritis independent of HLA-DR2 and HLA-DR3
(P58.531026). Consistent with a functional role in lupus nephritis, intra-renal mRNA levels of PDGFRA
and associated pathway members showed significant enrichment in patients with lupus nephritis (n=32)
compared with controls (n=15). Results fromthis large-scale genome-wide investigation of lupus nephritis
provide evidence of multiple biologically relevant lupus nephritis susceptibility loci.