Moreover, single nucleotide polymorphisms (SNPs) in the FKBP5 gene that increase its expression through a mechanism involving demethylation increase susceptibility to anxiety disorders, post-traumatic stress disorder (PTSD) and major depression [9]–[12], further implicating a role for increased levels of this protein in psychiatric illnesses. The gene discussed is FKBP5; the disease is post-traumatic stress disorder.