The A1 allele of the DRD2 TaqA1/A2 polymorphism as risk factor for PTSD

Background and Objectives: Dopaminergic neurotransmission is implicated in stress responses. The dopamine D2 receptor gene (DRD2) has been studied by the authors to assess its possible role as a predictor of those who are at a higher risk to develop PTSD after major psychological trauma. Methods: Over one year period 75 children and adolescents 6-18 yrs of age who had been exposed to moderate to severe burns were recruited from the burn unit at the Alexandria University Hospital for the study. Patients and their family were interviewed within the first 10 days of exposure. After signing a written consent form a 2 ml blood sample was obtained for genetic studies of the TaqA1/A2 polymorphism site of the DRD2 gene. Patients were reevaluated three and six months later for assessment of PTSD. Results: Among the 75 children recruited in the study, 26 died due to their burn injury, 19 dropped out as parents refused follow up and 30 continued the study follow up visits. Fourteen carried the A1A2 genotype. Of these 11(78.6%) developed PTSD. Sixteen carried the A2A2 genotype. Of these only one child (6.3%) developed PTSD. The results were significant at p < 0.001 with a relative risk 12.5. Conclusions: Following exposure to severe stress, the presence of the Taq A1 allele of the DRD2 gene results in a significant increase in the risk of developing PTSD.