An association study between the Val66Met polymorphism of the BDNF gene and postpartum depression

Postpartum depression disorder (PPD) is a severe illness affecting around 15% of deliveries. Several evidences suggest that PPD is, at least, partially genetic determined. The gene encoding BDNF is a strong candidate for pathogenesis of PPD since that it has been observed decrease of serum BDNF in patients suffering from PPD. The gene encoding BDNF has a polymorphism (Val66Met) that alters the regulated protein secretion; the methionine variant being associated with insufficient secretion compared with the Valine variant. We hypothesized that BDNF gene Val66Met polymorphism could be associated with PPD. We assessed 227 subjects randomly selected who had delivery at a maternity hospital using EPDS. Differences in genotype frequency were calculated by chi (2) test. Logistic Regression Analyses was performed to verify the existence of interaction between biological, psychiatric and environmental variables and PPD. Difference between groups was tested with Student's t test. Tests were two-tailed and results significant when p < or = 0.05. No difference in BDNF genotype distribution was observed between the depressed and non-depressed women. Educational level, stress during pregnancy, bipolar disorder and anxiety was strongly associated with PPD. We were not able to show an association between BDNF polymorphisms and PPD. Further studies are necessary to both of confirm our results and improve validity of PPD diagnosis.