In the meta-analysis, 2 SNPs achieved genome-wide significance levels (Pmeta-analysis< 5 108):BACH2in the full meta-analysis (Number 1A), andRAD51Bin the anti-CCPpositive subgroup (Number 1B). anticyclic citrullinated peptide (anti-CCP) antibody status, was performed. == Results == A significant association with RA risk (P< 0.05) was replicated for 6 of the SNPs assessed in the validation cohorts. All SNPs in the validation study had odds ratios (ORs) for RA susceptibility in the same direction as those in the O-Phospho-L-serine ImmunoChip finding study. One SNP, rs72928038, mapping to an intron ofBACH2, accomplished genome-wide significance in the meta-analysis (P= 1.2 108, OR 1.12), and a second SNP, rs911263, mapping to an intron ofRAD51B, was significantly associated in the anti-CCPpositive RA subgroup (P= 4 108, OR 0.89), confirming that both are RA susceptibility loci. == Summary == This study provides robust evidence for an association of RA TXNIP susceptibility with genes involved in B cell differentiation (BACH2) and DNA restoration (RAD51B). The finding that theRAD51Bgene exhibited different associations based on serologic subtype adds to the expanding knowledge foundation in defining subgroups of RA. Rheumatoid arthritis (RA) is definitely a complex, chronic autoimmune disease that affects 1% of the adult human population worldwide (1). In addition to inflammation of the synovial bones, RA is characterized by systemic swelling and the presence of serum autoantibodies against citrullinated peptides (anticitrullinated protein antibodies [ACPAs]), as defined by positive findings within the anticyclic citrullinated peptide (anti-CCP) antibody test (2). Genome-wide association studies have been successful in determining many loci associated with complex diseases, including RA (3). The energy of susceptibility variants within single genetic loci, in isolation, is likely to be limited, with evidence growing that linking multiple connected genes in pathways will lead to the better understanding of differing disease mechanisms (4,5). To accomplish robust pathway analysis, a comprehensive list of connected loci must be defined. Currently, 46 loci have been confirmed to become associated with RA susceptibility in Caucasians, at approved levels of genome-wide significance (P< 5 108), including 14 loci newly recognized in a recent high-density, fine-mapping (ImmunoChip) study of RA (6). In studies of inflammatory bowel disease (IBD), the findings have become much more helpful, implicating risk pathways that have not been previously recognized as important to this disease, and thus increasing the number of susceptibility markers from 92 to 163. The improved quantity of susceptibility loci for IBD has also enabled much more helpful investigation of disease overlap. Genetic studies of RA to day, albeit successful, have not yet delivered validated evidence of novel pathways. Moreover, disease overlap studies have been limited, therefore emphasizing the continuing need for finding of disease susceptibility markers in RA. RA is currently divided into 2 organizations based on serologic subtypes, which are defined according to the presence or absence of anti-CCP antibodies, although it is still unclear whether you will find biologic pathways that are common or unique to each group (2). Determining the genetic predisposition to each serologic subtype has the potential to better define the mechanism underlying each form of disease, enabling progress toward more focused clinical management. The most recent study aimed at identifying RA susceptibility loci (6) used a custom Illumina array (ImmunoChip), designed to interrogate 196,524 single-nucleotide polymorphisms (SNPs) for 186 loci that have O-Phospho-L-serine been previously shown to be O-Phospho-L-serine associated with a number of autoimmune diseases. The study by Eyre and colleagues was the first to be powered to analyze the subgroups of seronegative RA and seropositive RA separately. Genotyping in 11,475 RA instances and 15,870 settings provided evidence for 14 novel SNPs that.
