Fig. 5.

The BDNF rs1491850 SNP in the longitudinal analysis. Carrying the rs1491850 C allele (T/C or C/C) is associated with worse performance on UPDRS when treated with levodopa monotherapy, becoming significant at 12 and 24 months (a, p = 0.04 and p = 0.02, respectively), and this difference is also significant at 12 months in UPDRS-I (c, p = 0.04) but not UPDRS-II (e), UPDRS-III (g), or PDQ-39 (i). For subjects treated with strategies other than levodopa monotherapy, no differences between genotypes are observed by UPDRS, its parts I–III, or PDQ-39 (b, d, f, h, j, respectively). Values represent the mean ± SEM. * represents a significant comparison. Gray boxes correspond to C allele carriers; black boxes correspond to T/T subjects