A missense variant in NCF1 is associated with susceptibility to multiple autoimmune diseases

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease with a strong genetic component characterized by autoantibody production and a type 1 interferon signatures. Here we report a missense variant (g.74779296G>A; p.Arg90His) in NCF1, encoding the p47phox subunit of the phagocyte NADPH oxidase (NOX2), as the putative underlying causal variant that drives a strong SLE-associated signal detected by the lmmunochip in the GTF2IRD1-GTF2I region at 7q11.23 with a complex genomic structure. We show that the p.Arg90His substitution, which is reported to cause reduced reactive oxygen species (ROS) production(2), predisposes to SLE (odds ratio (OR) = 3.47 in Asians (P-meta = 3.1 x 10(-104)), OR = 2.61 in European Americans, OR = 2.02 in African Americans) and other autoimmune diseases, including primary Sjogren's syndrome (OR = 2.45 in Chinese, OR = 2.35 in European Americans) and rheumatoid arthritis (OR = 1.65 in Koreans). Additionally, decreased and increased copy numbers of NCF1 predispose to and protect against SLE, respectively. Our data highlight the pathogenic role of reduced NOX2-derived ROS levels in autoimmune diseases.