The current literature contains a few studies on the polymorphisms of the IFN-γ gene in the pathogenesis of various diseases—primarily viral and bacterial – but to our best knowledge, our study is the first to address the impact of IFN-γ gene polymorphisms in the context of the immune response to T. pallidum infection, the persistence of infection, and the occurrence of the serofast state in syphilis. This evidence concerns the gene IFNG and syphilis.