Polymorphic variants of proteasomal genes PSMA3 and PSMA6 in children with articular syndrome and juvenile idiopathic arthritis

A comparative analysis of three single nucleotide variations of the proteasomal genes PSMA3 (rs2348071) and PSMA6 (rs2277460 and rs1048990) was carried out in the groups of children from 1 to 16 years old with the autoimmune rheumatic disease - juvenile idiopathic arthritis (JIA; n = 199), with articular syndrome of non-autoimmune etiology (n = 229) and in the clinical control group with neither autoimmune nor chronic inflammatory diseases (n = 379). PCR, PCR–RFLP and real-time PCR were used for genotyping. It was found that the CG genotype and G allele of rs10489990 polymorphism (OR = = 1.93; 95 % CI 1.29-2.90; p = 0.002 and OR = 1.51; 95 % CI 1.11-2.04; p = 0.008 respectively), as well as the AA genotype of rs2348071 polymorphism (OR = 1.89; 95 % CI 1.02–3.49; p = 0.044) are associated with the JIA susceptibility, but not with articular syndrome. The established JIA risk genotypes may indicate the involvement of PSMA3 and PSMA6 genes in the development of an autoimmune reaction. In combination with other risk DNA markers, they can be proposed to assess a genetic predisposition to JIA. It was also revealed that the frequencies of risk genotypes and alleles for JIA in the group of patients with articular syndrome as a whole occupy an intermediate position between JIA and control group frequencies. This may indicate an increased JIA risk in some patients with articular syndrome.