Following an expert panel review of the efficacy and safety data on Single low dose (SLD) primaquine, the WHO recommended that the 0.75mg base/kg single P. falciparum transmission-blocking dose of primaquine be replaced by the lower dose of 0.25 mg/kg base without the requirement for prior G6PD testing; countries moving towards the elimination of malaria or needing to counter resistance to artemisinin-based antimalarials were encouraged to add this dose of primaquine to artemisinin-based combination therapies (ACTs) [5]. The gene discussed is G6PD; the disease is malaria.