Analysis of PPARGC1B, RUNX3 and TBKBP1 Polymorphisms in Chinese Han Patients with Ankylosing Spondylitis: A Case-Control Study

BACKGROUND Susceptibility to and severity of ankylosing spondylitis (AS) are largely genetically determined. PPARGC1B, RUNX3 and TBKBP1 have recently been found to be associated with AS in patients of western European descent. Our purpose is to examine the influence of PPARGC1B, RUNX3 and TBKBP1 polymorphisms on the susceptibility to and the severity of ankylosing spondylitis in Chinese ethnic majority Han population. METHODS Blood samples are drawn from 396 AS patients and 404 unrelated healthy controls. All the patients and the controls are Han Chinese and the patients are HLA-B27 positive. The AS patients are classified based on the severity of the disease. Twelve tag single nucleotide polymorphisms (tagSNPs) in PPARGC1B, RUNX3 and TBKBP1 are selected and genotyped. Frequencies of different genotypes and alleles are analyzed among the different severity AS patients and the controls. RESULTS After Bonferroni correction, the rs7379457 SNP in PPARGC1B shows significant difference when comparing all AS patients to controls (p = 0.005). This SNP also shows significant difference when comparing normal AS patients to controls (p = 0.002). The rs1395621 SNP in RUNX3 shows significant difference when comparing severe AS patients to controls (p = 0.007). The rs9438876 SNP in RUNX3 shows significant difference when comparing normal AS patients to controls (p = 0.007). The rs8070463 SNP in TBKBP1 shows significant difference in genotype distribution when comparing severe AS patients to controls (p = 0.003). CONCLUSIONS The rs7379457 SNP in PPARGC1B is related to susceptibility to AS in Chinese Han population. The rs7379457 SNP in PPARGC1B, the rs1395621 and rs9438876 SNPs in RUNX3, and the rs8070463 SNP in TBKBP1 are related to the severity of AS in Chinese Han population.