Cichon et al. [71] found an association between a 757C–T transition in exon 6 of the TPH2 gene, resulting in a pro206-to-ser (P206S) substitution (rs17110563) and bipolar affective disorder (125480) in two cohorts from Germany and Russia (883 patients and 1300 controls). Here, TPH2 is linked to bipolar disorder.