NFAT5 gene polymorphism as a risk factor of knee osteoarthrosis

Knee osteoarthrosis (OA) is a multifactorial disease with genetic factors playing an important part in its development. Our research goal was to examine associations between polymorphic variants rs1060105 and rs56116847 of SBNO1 gene, rs6499244 of NFAT5 gene and rs34195470 of WWP2 gene and developing stage 4 knee osteoarthrosis in people living in the Central Chernozem Region in Russia. Genotyping of polymorphic loci of candidate genes was accomplished in 95 patients with stage 4 knew osteoarthrosis and 500 people without the disease who were included into the reference group. We estimated associations between polymorphic loci of candidate genes and knee OA by using logistic linear regression within the allele, additive, recessive and dominant genetic models with gPLINK software. As a result, we replicated an association between a GWAS-significant rs6499244 polymorphism of NFAT5 gene and knee OA in people living in the Central Chernozem Region in Russia. An allele variant A of rs6499244 of NFAT5 gene was established to be “a risk factor” regarding stage 4 knee OA within the additive (OR = 1.61, рperm = 0.02) and recessive (OR = 2.07, рperm = 0.02) genetic models. The rs6499244 locus of NFAT5 gene is located in an area of DNAse I hypersensitivity; it increases DNA affinity to four transcription factors (CDP_6, RFX5_known1, RORalpha1_2, TCF4_known1); it is localized in functionally active promoters and enhancers; it is associated with expression of nine genes (CLEC18A, COG4, EXOSC6, NFAT5, NOB1, NPIPB14P, NQO1, PDXDC2P, SMG1P7) and alternative mRNA splicing of three genes (NOB1, NPIPB14P, NQO1) in various organs and tissues in the body including those that are pathogenetically significant for OA (fat tissue, tibial nerves and arteries, and skeletal muscles).