HTR6 and Parkinsonism: Nominally significant associations of the HTR6 rs1805054 genotype with ESRS subscale II for parkinsonism (H = 6.06, p = 0.048) and ESRS-based rigidity (H = 6.90; p = 0.032) scores were rejected due to the Bonferroni correction (Supplementary Table S4).