Once established in the nasopharynx, Spn is capable of causing localized inflammation of the upper-respiratory tract resulting in sinusitis, ascending the Eustachian tubes to cause otitis media, being aspirated to cause pneumonia, and, once in the lower respiratory tract, escaping into the bloodstream to cause bacteremia/sepsis and disseminated organ damage including meningitis (Figure 1). The gene discussed is SPN; the disease is susceptibility to pneumonia measurement.