Functional polymorphism of the glucocorticoid receptor gene associates with mania and hypomania in bipolar disorder

In affective disorders, dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis is a frequently observed phenomenon. Subtle changes in glucocorticoid receptor (GR) functioning caused by polymorphisms of the GR gene (NR3C1) may be at the base of the altered reaction of the HPA axis to stress and subsequently related to the development and course of affective disorders. The aim of our study is to evaluate associations between GR gene polymorphisms and bipolar disorder (BD). In this study, 245 patients with BD were interviewed to confirm diagnosis and BD subtype. Data on medication use and sociodemographic details were also collected. The control group consisted of 532 healthy blood donors, from which data on sex and age were collected. To perform genotyping, blood was collected from all patients and healthy controls. A trend was found for a protective effect of the exon 9 beta polymorphism (p = 0.14) and the TthIIII polymorphism (p < 0.05) on the manifestation of the disease. These effects were significantly influenced by male gender for both polymorphisms. Patients with BD and the A/G variant in exon 9 beta had significantly fewer manic and hypomanic episodes than noncarriers (p < 0.05). No further associations were found with the other investigated GR gene polymorphisms and BD. These findings were not corrected for multiple comparisons. We conclude that the exon 9 beta polymorphism and the TthIIII polymorphism of the GR gene may be associated with a protective effect on the clinical manifestation and course in patients with BD. Furthermore, no associations were found between the other studied GR gene polymorphisms and this disease.