Although a detailed assessment of the effects of PspC expression on S. mitis virulence is complicated by the species-specificity of the PspC/factor H interaction, when tested by competitive infection experiments after pre-incubation in human FH there was no difference in virulence in mice between the wild type and pspC + S. mitis strains. The gene discussed is SFTPC; the disease is familial hyperaldosteronism.