Genetic variation of cytokines could effect recovery from Traumatic Brain Injury

Research led by Ryan Waters at the Wessex Neurological Centre published last week in The Journal of Neurotrauma reports a significant effect of a single nucleotide polymorphism of a TNFA on clinical outcome following traumatic brain injury (TBI). This epidemiological study tested 1,096 patients who had suffered brain injury, defined as any mechanical force which results in brain dysfunction arising from a myriad of causes (e.g. falling, shaken baby syndrome).

Patients were genotyped for Single Nucleotide Polymorphisms (SNPs) that had previously been associated with disease outcome. SNPs are differences in a single nucleotide between individuals. This genetic variation is not classed as ‘mutation’ due to a relatively high prevalence in the population (i.e. >1%). SNPs are often found between genes rather than in them and there is increasing interest in their role in the development of complex phenotypes that may be controlled by many small genetic variations. The site of the SNPs in this study was near, or in, the genes for cytokines, including Tumour Necrosis Factor Alpha (TNFA) and IL1A, which are involved in the inflammatory response that occurs following TBI. Concurrently, patients were also assessed on the ‘Glasgow Outcome Scale’ 6 months after the injury. By combining these data the researchers hoped to identify correlations between SNPs present in an individual and their clinical outcome.

On one allele of TFNA, 308 SNPs appeared to have a significant relationship with an ‘unfavourable’ outcome following TBI. 39% of allele carriers were rated on the Outcome Scale as having made poor recovery, compared to 31% of non-carriers (p<0.05). The monitoring as to whether this correlation is sustained for longer than 6 months should help in the treatment of patients suffering from ‘brain damage’.

http://www.liebertpub.com/global/pressrelease/does-genetic-variability-affect-long-term-response-to-traumatic-brain-injury/1337/