Therefore, microglia respond to excessive TGF-β exposure with the expression of genes associated with phagocytosis of synapses and myelin and downregulation of neurotrophic factors as well as increased expression of the C4 implicated in the hypothesis of abnormal synaptic pruning in schizophrenia [82, 88, 89]. The gene discussed is TGFB1; the disease is schizophrenia.