While MPO is central to neutrophil function and is essential for the formation of NETs (Metzler et al., 2014), 95% of the individuals with MPO deficiency were reported to be asymptomatic (Ren and Fedoriw, 2012), and indicating that MPO inhibition may be, to a wide extent, tolerable for proper immune function. The gene discussed is MPO; the disease is hyperinsulinemic hypoglycemia, familial, 4.