Overall n = 156 TPPA: sensitivity 100% and specificity 99.2% VDRL: sensitivity 83.3% and specificity 100% Pathozyme IgM: sensitivity 88.5% and specificity 96.0% Primary syphilis n = 59 TPPA: sensitivity 100% VDRL: sensitivity 61.0% Pathozyme IgM: sensitivity 89.8% Secondary syphilis n = 66 TPPA: sensitivity 100% VDRL: sensitivity 97.0% Pathozyme IgM: sensitivity 90.9% Latent syphilis n = 25 TPPA: sensitivity 100% VDRL: sensitivity 96.0% Pathozyme IgM: sensitivity 84.0% The gene discussed is CD40LG; the disease is syphilis.