​The South African Research Chair (SARChI) in Posttraumatic Stress Disorder held by Prof Soraya Seedat, has a strong gene-brain-behaviour research focus, and aims to identify through state-of-the-art genetic and brain imaging methods the genetic, biological and environmental factors that contribute to increasing or decreasing a person's risk for developing posttraumatic stress disorder (PTSD) once he or she has been exposed to trauma.

The main focus of the neuropsychiatric genetics research group, which falls under Seedat via the Department of Psychiatry's SARChI grant, is to identify and determine molecular mechanisms that result in the development of stress-related disorders and PTSD in particular. Family and twin studies indicate that a genetic component contributes to the cause of the stress-related disorders, but to date no gene variants have been conclusively identified as risk factors.

This may be because present candidate gene-based studies are limited in their selection of genes, given the currently incomplete knowledge about the pathophysiology of PTSD.

In addition, the role of the environment in the study of causation of PTSD cannot be underestimated.

“The overarching aim of our neuropsychiatric genetics group is to interrogate PTSD on a genetic, epigenetic, cellular and environmental level to identify genomic, epigenomic, transcriptomic, proteomic and metabolomic signatures that increase risk of developing PTSD, and to clarify biomachinery underlying the disorder," says Prof Sian Hemmings, who heads the Neuropsychiatric Genetics Laboratory.

Recent studies have investigated the association between candidate genes and increased levels of anxiety sensitivity in adolescents. Their analysis revealed gender- and ethnicity specific risks for the development of anxiety sensitivity, both with and without the interaction of childhood trauma. Also,

Exciting preliminary results from a large whole transcriptomic sequencing project on PTSD indicate that sodium voltage-gated channel alpha subunit 2 (SCN2A) is downregulated in PTSD individuals compared to trauma-exposed controls. “Although the results await verification, they are intriguing, given that SCNA2 is associated with neurodevelopmental disorders such as autism and schizophrenia," says Hemmings.

 *The article appears in the latest edition of the Stellenbosch University Research Publication. Click here to read more. 

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