Genetic polymorphisms in the P2X7 gene and its association with susceptibility to tuberculosis

BACKGROUND: Several studies have reported the influence of genetic variations on susceptibility to tuberculosis (TB). Polymorphism in P2X7 gene coding for P2X7 receptor present on macrophages has been linked to TB in different populations. OBJECTIVE: To assess the role of P2X7 gene -762T/C and -1513A/C polymorphisms in TB susceptibility. DESIGN: In a case-control study, polymerase chain reaction (PCR) amplification of genomic DNA extracted from peripheral blood samples of cases and controls was followed by restriction fragment length polymorphism or allele-specific PCR. RESULTS: The 1513C allele was found to be associated with TB susceptibility (P = 0.02, OR for variant C allele 1.33, 95%CI 1.03-1.73). A significant protective association against TB was found for -762T1C polymorphism (P < 0.01, OR for variant C allele 0.72, 95%CI 0.57-0.91). On classifying samples on the basis of sex, only males showed a significant association between P2X7 -1513A1C and P2X7 762T/C and TB in the present study. CONCLUSION: A significant association of 762T/C and 1513A/C polymorphisms with TB in the P2X7 gene was found in our study population. A sex bias, with only males showing a significant association with the disease, is the first report of this kind. Genetic studies for the characterisation of the susceptibility genes can help to gain a better understanding of TB pathogenesis.