GRN and hyperinsulinemic hypoglycemia, familial, 4: The Trem2 gene modulates the expression of triggering receptor expressed on myeloid cells-2 (Trem2), which has been shown to be upregulated in the serum of SCI patients [84], and controls microglia hyperactivation in a model of progranulin deficiency [74], along with the transition of microglia towards a proinflammatory phenotype and exacerbation of neuropathic pain [72].