OBJECTIVES: A single nucleotide polymorphism in the NCF1 gene (NCF1-339, rs201802880), encoding NADPH oxidase type II subunit NCF1/p47<sup>phox</sup>, reducing production of reactive oxygen species (ROS) is strongly associated with the development of systemic lupus erythematosus (SLE).
Genome-wide association studies of systemic lupus erythematosus (SLE) in Chinese and Korean populations demonstrated strong association of single nucleotide polymorphisms (SNPs) located in the GTF2I-NCF1 region, rs73366469 (GTF2I), rs117026326 (GTF2I), rs80346167(GTF2IRD1) and rs201802880 (NCF1).
We show that the p.Arg90His substitution, which is reported to cause reduced reactive oxygen species (ROS) production, predisposes to SLE (odds ratio (OR) = 3.47 in Asians (P<sub>meta</sub> = 3.1 × 10<sup>-104</sup>), OR = 2.61 in European Americans, OR = 2.02 in African Americans) and other autoimmune diseases, including primary Sjögren's syndrome (OR = 2.45 in Chinese, OR = 2.35 in European Americans) and rheumatoid arthritis (OR = 1.65 in Koreans).
We aimed at investigating association and function of the missense single nucleotide polymorphism (SNP), rs201802880 (here denoted NCF1-339) in <i>NCF1</i> with systemic lupus erythematosus (SLE).