As a stressor, childhood trauma may participate in the pathogenesis of BD via the following mechanisms: (1) altering the developmental progression of the brain; (2) systemic inflammation; (3) alterations in hypothalamic-pituitary-adrenal (HPA) axis function, and disturbance of corticotropin-releasing factor (CRF) neural systems; and (4) genetic influence, such as expression of HPA axis genes, single nucleotide polymorphic gene variants (SNPs) [37]. The gene discussed is CRH; the disease is Behcet disease.