Analysis of functional SNP in ifng/ifngr1 in Chinese Han population with tuberculosis.

Ifng/Ifngr1 are the main genes that are associated with tuberculosis. We continued to search for other functional single nucleotide polymorphisms (SNP) and investigated their influence on patients with tuberculosis in the Chinese population. Seven SNP located in the ifng and ifngr1 genes were genotyped by ligase detection reaction in 222 cases and 188 ethnically matched controls. A significant genetic association between rs7749390 (located on the exon/intron splice site of the ifngr1 gene) and tuberculosis was observed, and the log-additive model was accepted as the best inheritance model to fit these data (OR: 1.35, 95% CI: 1.02-1.80, P = 0.038). Haplotype-specific association analysis revealed that the result was consistent with the individual SNP study. The combination of rs2234711/rs1327474/rs7749390/rs41401746, which was in strong linkage disequilibrium (D' > 0.75), showed a significant association of ifngr1 with tuberculosis (P = 0.00079). Neither the single SNP nor the haplotype analysis showed a significant association between tuberculosis and the ifng gene markers. Our data implied the involvement of the ifngr1 gene in susceptibility to tuberculosis.