No association between the +874T/A single nucleotide polymorphism in the IFN-γ gene and susceptibility to TB

A single nucleotide polymorphism (SNP), +874T/A, in the first intron of the interferon-gamma (IFN-γ) gene, has presented associations with human susceptibility to tuberculosis (TB) in some ethnic populations, but not in others. In this population-based case-control study with adult TB patients from Houston, Texas, we found no significant differences of +874T/A genotypic frequencies between cases and ethnically-matched controls or between advanced forms of TB disease (extra-pulmonary involvement or presence of cavitary disease) and pulmonary TB. Given possible sample size limitations, our results suggest that the IFN-γ +874T/A mutation has no association with TB susceptibility or TB disease severity.