Blood and brain transcription-wide association and differential gene expression studies of PTSD have also implicated some of these genes, including a blood-based prediction of downregulation of ARFGEF2 in the dorsolateral prefrontal cortex (48) and a postmortem study of human PTSD cortex indicating downregulation of CTSS expression in the dorsal anterior cingulate cortex and downregulation of OSBPL3 expression in the dorsolateral prefrontal cortex (49). The gene discussed is CTSS; the disease is post-traumatic stress disorder.