In the present study, C3 complement (C3/C3c) levels were significantly decreased in LBD and MSA patients compared to the CG, and C4 complement (C4/C4c) levels were significantly decreased in MSA patients compared to the CG (see Table 3), likely reflecting activation of the complement system and C3/C4 complement consumption. The gene discussed is C3; the disease is multiple system atrophy.