FKBP5 and post-traumatic stress disorder: Van Zuiden et al. noted that vulnerability to PTSD includes various dysregulations of the glucocorticoid signaling cascade, including low FKB5 levels in peripheral blood mononuclear cells (PBMC) prior to trauma and single nucleotide polymorphisms (SNP) in genes associated with glucocorticoid signaling such as FKBP5 [61].