Fig. 1

a, b DNA methylation at the BDNF IV promoter in blood and saliva of BPD patients (T1) (N = 41 for saliva, N = 39 for blood) as compared to healthy controls (N = 41). Data shown for single CpG sites (a) and average methylation calculated over all analyzed CpG sites (b), error bars represent SEM. Three asterisks (***) indicate statistical significance at p value < 0.001. c Schematic drawing of the BDNF gene with exons 1–9. Analyzed CpG sites (marked in green) are within the exon IV promoter, in direct vicinity of the transcription start site (TSS)