Objective: Tuberculosis is still a public health problem. Host genetic factors, such as polymorphisms in NRAMP1 gene, may play a role in the development of tuberculosis. To clarify the effect of NRAMP1 gene polymorphisms on the development of childhood tuberculosis, the association of NRAMP1 gene polymorphisms with susceptibility to tuberculosis in the ethnic Han Chinese children was investigated.
Methods: From January 2005 to March 2008, 130 ethnic Han children with tuberculosis (TB group) were enrolled. Three hundred and ninety hospitalized ethnic Han children for physical examination in the surgery department were used as the control group. The controls were matched with tuberculosis children by age, sex and area. PCR-RFLP analysis was performed on DNA samples to identify allele genotypes of INT4 and D543N in NRAMP1 gene. Genotype frequency differences between tuberculosis patients and controls were analyzed using x2 test.
Results: No statistical difference was found in the genotype frequency of variants G/C and C/C at the INT4 locus between the TB and the control groups. At the D543N locus, the frequency of genotype variants (G/A and A/A) was significantly higher in the TB group (34/130) than that in the control group (66/390) (x2=5.349, P<0.05; OR=1.74, 95%CI=1.08-2.79). When stratified by sex, differences in the genotype distribution were observed only in females at the D543N locus, which the variant genotypes were higher in the TB group (16/52) than in the control group (21/155) (x2=7.866, P<0.05; OR=2.84, 95%CI=1.34-5.99). For males, there was no difference between the TB and the control groups. At the INT4 locus, no difference was observed between the two groups in boys and girls.
Conclusions: Genotypic variation at the D543N locus in NRAMP1 gene may be associated with susceptibility to tuberculosis in ethnic Han Chinese children. Variant genotypes in NRAMP1 gene (G/A and A/A) may be susceptible genotypes to tuberculosis in ethnic Han Chinese children. Girls with variant genotypes were more susceptible to tuberculosis.