Association of single nucleotide polymorphisms in the CD209, MMP9, TNFA and IFNG genes with susceptibility to Japanese encephalitis in children from North India.

Japanese encephalitis (JE), an acute encephalitis syndrome disease caused by infection with JE virus (JEV), is an important mosquito borne disease in developing countries. The clinical outcomes of JEV infection show inter individual differences. Only in a minor percent of the infected subjects, the disease progresses into acute encephalitis syndrome. Single nucleotide polymorphisms in the host immune response related genes are known to affect susceptibility to JE. In the present study, 238 JE cases and 405 healthy controls (HCs) without any known history of encephalitis were investigated for SNPs in the CD209 MX1, TLR3, MMP9, TNFA and IFNG genes which are important in the immune response against JEV by PCR based methods. The results revealed higher frequencies of heterozygous genotypes of CD209 rs4804803, MMP9 rs17576, TNFA rs1800629 and IFNG rs2430561 in JE cases compared to HCs. These SNPs were associated with JE in an over-dominant genetic model (Odds ratio with 95% CI 1.51 (1.09-2.10) for CD209 rs4804803, 1.52 (1.09-2.11) for MMP9 rs17576, and 1.55 (1.12-2.15) for IFNG rs2430561). The association of G/A genotype of TNFA rs1800629 with JE was confirmed in a larger sample size. The results suggest the association of CD209 rs4804803, MMP9 rs17576, IFNG rs2430561 and TNFA rs1800629 polymorphisms with susceptibility to JE.