Sobue et al.46 suggested that a loss of homeostatic microglia is associated with neurodegeneration, because homeostatic genes including p2ry12 were decreased in the microglia of tauopathy and motor neuron disease model mice accompanying neuronal loss, but not in the microglia of AppNL-G-F mice, which do not show neuronal loss. The gene discussed is P2RY12; the disease is tauopathy.