Progranulin deficiency has been shown to cause microglial activation in an age‐dependent manner (Martens et al, 2012; Lui et al, 2016; Kao et al, 2017; Takahashi et al, 2017; Gotzl et al, 2019). The gene discussed is GRN; the disease is hyperinsulinemic hypoglycemia, familial, 4.