TRAF1/C5 rs3761847 SNP Is Associated with Severe Pattern of Rheumatoid Arthritis in Greek Patients

The era of whole genome study analysis has introduced a profound research in the genetics of autoimmune diseases. Some of the new genetic loci that have been associated with the development or the severity of autoimmune diseases have been thoroughly studied, conferring a more detailed understanding of disease pathophysiology. Furthermore, single nucleotide polymorphisms (SNPs) have been described not only in coding regions of the human genome but also in non-coding areas (introns), the importance of which has not been yet clarified. Over the last years, such an SNP has been associated with the development of rheumatoid arthritis, the most frequent autoimmune disease. This SNP is at the position 122730060 of chromosome 9 in the TRAF1/C5 region and consists of a substitution of the nucleotide base guanine (G)—which is considered the ancestral phenotype— by alanine (A). It has been indicated that G is the aggravating nucleotide, and that G/G is the disease predisposing phenotype, conferring >1.3× risk for RA. On this background, we performed a genome study on a Greek population of northern Greece (Macedonia) in order to identify the association of this SNP with RA in our group.