Oxytocin is a peptide hormone and neuropeptide that is involved in the regulation of mood, anxiety and social biology. It plays a role in social bonding, sexual reproduction in both sexes, and during and after childbirth. The protein encoded by the OXTR gene belongs to the G-protein coupled receptor family and acts as a receptor for oxytocin. Its activity is mediated by G proteins which activate a phosphatidylinositol-calcium second messenger system.
The A allele is associated with a change in OXTR function such that there is decreased sensitivity to social cues, especially in a stressful environment.
Individuals with the AG genotype may have a lower empathetic ability and a decreased ability to manage stressful situations, with an increased risk for post-traumatic stress disorder, especially with exposure to adverse childhood events. Individuals who carry the risk variant may require more intensive follow up after exposure to an environmental stressor.