H1-5 and amyotrophic lateral sclerosis: Proteins including HIST1H2 AB, HIST1H1B, HIST1H1E, HIST1H4 A, H2 AFZ, and HIST2H2BF as well as those related to chemical synaptic transmission and assembly of postsynaptic elements in C9orf72 ALS CSF were significantly decreased in abundance relative to sALS.