Association of BTNL2 rs2076530 SNP with Graves' disease is secondary to DRB1 exon 2 position beta74

OBJECTIVE: The HLA region encodes numerous immune response genes, with the DR/DQ molecules consistently associated with autoimmune disease (AID). Recent studies in sarcoidosis have identified association of a single nucleotide polymorphism (SNP) rs2076530 within BTNL2, a potential T-cell inhibitor, independent of the known DRB1 association. The aim of this study was to investigate the association rs2076530 with disease in a large UK Caucasian Graves' disease (GD) dataset. DESIGN: A case control association study of the rs2076530 polymorphism. PATIENTS: Eight hundred sixty-four Graves' disease patients and 864 controls. MEASUREMENTS: Tests for association with disease. RESULTS: We detected association of rs2076530 within a large GD dataset [OR = 1.32 (95% CI = 1.14-1.52)], however, linkage disequilibrium (LD) analysis revealed association of rs2076530 to be secondary to the previously established DRB1 exon 2 encoded position beta74 effect although a rare haplotype effect, including both loci, cannot be excluded. CONCLUSIONS: BTNL2 may be a sarcoidosis-specific susceptibility loci, although only extensive examination of the whole HLA region in different inflammatory/AIDs will enable DR/DQ independent HLA effects to be determined.