Single-nucleotide polymorphism and haplotypes of TNIP1 associated with systemic lupus erythematosus in a Chinese Han population

Objective: To determine the association of systemic lupus erythematosus (SLE) with single-nucleotide polymorphisms (SNP) in the TNIP1 gene and compare the expression of this gene in cases and controls from a Chinese Han population in this replication study.

Methods: Matrix-assisted laser desorption ionization time-of-flight mass spectrometry was used to genotype 19 SNP in TNIP1 in Chinese Han patients with SLE (n = 341) and controls (n = 356). Genotypes were analyzed by codominant, dominant, and recessive models. Analysis of allele frequencies and linkage disequilibrium was also performed. Western blotting and qRT-PCR were used to measure the expression of these genes in peripheral blood mononuclear cells of SLE cases and controls.

Results: Seven SNP loci were significantly associated with SLE in our population (p < 0.05 for all comparisons). Two TNIP1 gene haplotypes (ATTGCGC and GTCCTAT) were associated with SLE (p = 0.0246 and p = 0.0024, respectively). Western blotting and qRT-PCR results provide evidence that patients with SLE had significantly reduced expression of TNIP1/ABIN-1 relative to controls.

Conclusion: Analysis of SNP in the TNIP1 gene and expression of this gene in peripheral blood lymphocytes indicated these SNP were associated with the occurrence of SLE in Han Chinese patients. Future studies should examine the roles of these SNP in the pathogenesis of SLE.