DRD2 and Borderline personality disorder: Regarding monoamine receptor genes, within a large-scaled study on subjects with bulimia spectrum disorders (BSD) with and without comorbid BPD Groleau et al. (24) found significant but marginally increased methylation of the dopamine D2 receptor gene (DRD2) exon 1 promoter region in whole peripheral blood cell (PBC) DNA of subjects with BSD and BPD compared with that of subjects with BSD only.