CpG methylation of brain-derived the neurotrophic factor gene promoter as a potent diagnostic and prognostic biomarker for post-traumatic stress disorder.

Posttraumatic stress disorder (PTSD) is a common response to traumatic events. Many PTSD patients recover in the next few months, but in a significant subgroup, the symptoms persist, often for years. The present study shows that brain-derived neurotrophic factor (BDNF) gene is related to the pathological mechanism of a variety of mental diseases. Here we investigate the effect of methylation of BDNF gene and different loci on the occurrence and development of PTSD. Initially, using case-control method, 322 PTSD patients as well as 215 normal controls were selected as the subjects. Following peripheral venous blood being collected from the subjects, genomic DNA was extracted. Methylation of the cytosine-guanine dinucleotide (CpG) island in BDNF gene promoter was then modified by bisulfite and detected through direct sequencing. Methylation of CpG in BDNF gene promoter was closely related to PTSD, and the methylation level of CpG in BDNF gene promoter may serve as a biomarker for PTSD diagnosis. Types of trauma of PTSD patients may have a certain effect on the methylation level of BDNF gene promoter. Methylation level of the BDNF promoter, depressive degree score, poor sleep quality score, early trauma score, mental stress score, and trauma type were closely related to the occurrence and development of PTSD. Taken together, our data support the notion that stressful life events may directly cause CpG methylation in the BDNF promoter of PTSD patients. Stress types may be associated with methylation levels of CpG1, CpG7, and CpG18 in the BDNF promoter of PTSD patients. These findings provide a new way for the diagnosis and treatment of PTSD.