Association analysis of the proneurotensin gene and bipolar disorder.

Neurotensin (NT) localizes within dopaminergic neurones in the mesocortical, mesolimbic and nigrostriatal systems, and it is now clear that NT can selectively modulate dopaminergic neurotransmission. It has therefore been proposed that altered NT function might contribute to the pathogenesis of neuropsychiatric disorders in which disordered dopaminergic neurotransmission is suspected. We have previously screened the gene encoding NT in a sample of schizophrenic and bipolar subjects, and identified three sequence variants. These have now been tested for association with bipolar disorder using a case-control sample of unrelated bipolar subjects and matched controls. No evidence for association was found, and our data therefore suggest that sequence variation in this gene does not make an important contribution to susceptibility to bipolar disorder.