Association of SP110 gene polymorphisms with susceptibility to tuberculosis in a Chinese population

Development of tuberculosis is mediated by both environmental and genetic factors. The Ipr1 (intracellular pathogen resistance-1) gene has been identified at the sst1 (super-susceptibility to tuberculosis 1) locus on mouse chromosome 1. As Ipr1 plays a major role in mediating innate immunity in a mouse model of Mycobacterium tuberculosis infection, the human Ipr1 homologue, SP110 is a recognised candidate gene for control M. tuberculosis infection. This study was designed to investigate sequence variants of the SP110 gene in Chinese and test whether the SP110 gene is a susceptibility factor for tuberculosis. In a sample of 308 smear-positive patients with pulmonary tuberculosis and 628 exposed, apparently healthy controls, we have genotyped 6 SP110 gene variants that were either available from public databases, including HapMap data, or identified by DNA re-sequencing. DNA re-sequencing revealed 7 novel SP110 variants in the 5'-UTR and intronic regions. Two of SP110 SNPs, rs11556887 and rs1135971 were significantly associated with disease. Analysis of the haplotypes revealed two haplotypes are significantly associated with TB. Other variants of SP110 in this case-control approach could not find any significant differences. Our study demonstrates that genotypes and haplotypes of SP110 might be associated with susceptibility to tuberculosis in Chinese population.