Investigators at the National Institutes of Health have observed that the survival rate of people with a rare immunodeficiency disease called chronic granulomatous disease (CGD) is greatly improved when even very low levels of microbe-killing molecules are present. Because production of these molecules, made by an enzyme called NADPH oxidase, can be predicted from genetic analysis, a patient’s risk for severe CGD could be assessed very early in life, allowing for more personalized treatment, say the researchers.