Brain- and blood-derived Vpr sequences. (A) Brain-derived sequences exhibited diversity in both the HAD and ND groups but a mutation at position 77 significantly distinguished the clinical groups with a Q predominating in the HAD group and an R being most evident in the ND group. (B) Blood-derived sequences also demonstrated molecular heterogeneity in both groups but there were no residues that distinguished the clinical groups. (C) The frequency of within-groups synonymous mutations was similar among all sequences from all clinical groups. (D) The frequency of within-group non-synonymous mutations was lower in the brain-derived HAD sequences compared with the blood-derived HAD sequences. (E) Conversely, the ratios of within-group non-synonymous to synonymous mutations did not differ within the clinical groups. (F) The frequency of detecting vpr sequences in brain was significantly higher in the HAD group compared with the ND groups (A, B, F: Mann-Whitney U test; C-D: ANOVA, Bonferroni post hoc test; *p < 0.05).