Furthermore, a polymorphism of NO gene, nitric oxide synthase 1 adaptor protein (NOS1AP) and a BDNF variant, Val66Met, were associated with severe PTSD, emphasizing the importance of NO/BDNF dialog in this disorder (Chen et al., 2006; Bruenig et al., 2017; Pitts et al., 2019). The gene discussed is BDNF; the disease is post-traumatic stress disorder.