Studies have confirmed that neurofilament light chain (NFL), α-synuclein, glial fibrillary acidic protein (GFAP), brain-derived neurotrophic factor (BDNF), and triggering receptor expressed on myeloid cells-2 (TREM2) do not show significant correlation with fatigue and its progression in MSA. This evidence concerns the gene GFAP and multiple system atrophy.