In this sense, deficiencies in key genes for microglial survival and/or proliferation (such as CSF1R or TREM2) are associated with rare hereditary neurodegenerative diseases, such as adult-onset leukoencephalopathy with axonal spheroids or Nasu–Hakola disease (respectively) [6, 38, 39]. The gene discussed is CSF1R; the disease is neurodegenerative disease.