Our results add to a growing literature on BDNF methylation in BD by the use of precise mass spectrometry assays of CpGs in previously uninvestigated BDNF promoters in one of the largest BD epigenetics samples of peripheral tissue to date; they underscore the complexity of BDNF regulation across nine functional promoters and multiple transcripts and altogether suggest a need for more comprehensive epigenetic investigation of the locus. Here, BDNF is linked to Behcet disease.