C9orf72 and frontotemporal dementia: The brains of FTD/ALS patients with the C9orf72 repeat expansion show not only the classical pathology, characterized by neuronal loss and astroglial and microglial activation prominent in the frontotemporal cortex, and degeneration of motor neurons in the spinal cord, but also the TAR DNA-binding protein-43 (TDP-43) pathology designated type B and/or type A most evident in the hippocampus [5-10].