Together, these studies indicate a role for C9orf72 astrocytes in the neurodegeneration of motor neurons observed in C9orf72-ALS/FTD; however, there is little to no information on the role of astrocytes in the neurodegeneration of cortical neurons leading to dementia symptoms in this disease spectrum. The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.