Long Noncoding RNA VLDLR-AS1 Levels in Serum Correlate with Combat-Related Chronic Mild Traumatic Brain Injury and Depression Symptoms in US Veterans.

More than 75% of traumatic brain injuries (TBIs) are mild (mTBI) and military service members often experience repeated combat-related mTBI. The chronic comorbidities concomitant with repetitive mTBI (rmTBI) include depression, post-traumatic stress disorder or neurological dysfunction. This study sought to determine a long noncoding RNA (lncRNA) expression signature in serum samples that correlated with rmTBI years after the incidences. Serum samples were obtained from Long-Term Impact of Military-Relevant Brain-Injury Consortium Chronic Effects of Neurotrauma Consortium (LIMBIC CENC) repository, from participants unexposed to TBI or who had rmTBI. Four lncRNAs were identified as consistently present in all samples, as detected via droplet digital PCR and packaged in exosomes enriched for CNS origin. The results, using qPCR, demonstrated that the lncRNA VLDLR-AS1 levels were significantly lower among individuals with rmTBI compared to those with no lifetime TBI. ROC analysis determined an AUC of 0.74 (95% CI: 0.6124 to 0.8741; p = 0.0012). The optimal cutoff for VLDLR-AS1 was ≤153.8 ng. A secondary analysis of clinical data from LIMBIC CENC was conducted to evaluate the psychological symptom burden, and the results show that lncRNAs VLDLR-AS1 and MALAT1 are correlated with symptoms of depression. In conclusion, lncRNA VLDLR-AS1 may serve as a blood biomarker for identifying chronic rmTBI and depression in patients.

Discovery of novel microRNAs and their pathogenic responsive target genes in mild traumatic brain injury.

MicroRNAs (miRNAs) are non-coding RNA molecules that function in RNA silencing and post-transcriptional regulation of gene expression. They are profound mediators of molecular and cellular changes in several pathophysiological conditions. Since miRNAs play major roles in regulating gene expression after traumatic brain injury (TBI), their possible role in diagnosis, prognosis, and therapy is not much explored. In this study, we aimed to identify specific miRNAs that are involved in the pathophysiological conditions in the first 24 h after mild TBI (mTBI). The genome-wide expression of miRNAs was evaluated by applying RNA sequence in the injury area of the cerebral cortex 24 after inflicting the injury using a mouse model of mild fluid percussion injury (FPI; 10 psi). Here, we identified different annotated, conserved, and novel miRNAs. A total of 978 miRNAs after 24 h of TBI were identified, and among these, 906 miRNAs were differentially expressed between control and mTBI groups. In this study, 146 miRNAs were identified as novel to mTBI and among them, 21 miRNAs were significant (p < 0.05). Using q-RT-PCR, we validated 10 differentially and significantly expressed novel miRNAs. Further, we filtered the differentially expressed miRNAs that were linked with proinflammatory cytokines, apoptosis, matrix metalloproteinases (MMPs), and tight junction and junctional adhesion molecule genes. Overall, this work shows that mTBI induces widespread changes in the expression of miRNAs that may underlie the progression of the TBI pathophysiology. The detection of several novel TBI-responsive miRNAs and their solid link with pathophysiological genes may help in identifying novel therapeutic targets.

Concussion-Associated Gene Variant COMT rs4680 Is Associated With Elite Rugby Athlete Status.

OBJECTIVE: Concussions are common match injuries in elite rugby, and reports exist of reduced cognitive function and long-term health consequences that can interrupt or end a playing career and produce continued ill health. The aim of this study was to investigate the association between elite rugby status and 8 concussion-associated risk polymorphisms. We hypothesized that concussion-associated risk genotypes and alleles would be underrepresented in elite rugby athletes compared with nonathletes. DESIGN: A case-control genetic association study. SETTING: Institutional (university). PARTICIPANTS: Elite White male rugby athletes [n = 668, mean (SD) height 1.85 (0.07) m, mass 102 (12) kg, and age 29 (7) years] and 1015 nonathlete White men and women (48% men). INTERVENTIONS: Genotype was the independent variable, obtained by PCR of genomic DNA using TaqMan probes. MAIN OUTCOME MEASURE: Elite athlete status with groups compared using χ 2 and odds ratio (OR). RESULTS: The COMT rs4680 Met/Met (AA) genotype, Met allele possession, and Met allele frequency were lower in rugby athletes (24.8%, 74.6%, and 49.7%, respectively) than nonathletes (30.2%, 77.6%, and 54.0%; P < 0.05). The Val/Val (GG) genotype was more common in elite rugby athletes than nonathletes (OR 1.39, 95% confidence interval 1.04-1.86). No other polymorphism was associated with elite athlete status. CONCLUSIONS: Elite rugby athlete status is associated with COMT rs4680 genotype that, acting pleiotropically, could affect stress resilience and behavioral traits during competition, concussion risk, and/or recovery from concussion. Consequently, assessing COMT rs4680 genotype might aid future individualized management of concussion risk among athletes.

Severe NAD(P)HX Dehydratase (NAXD) Neurometabolic Syndrome May Present in Adulthood after Mild Head Trauma.

We have previously reported that pathogenic variants in a key metabolite repair enzyme NAXD cause a lethal neurodegenerative condition triggered by episodes of fever in young children. However, the clinical and genetic spectrum of NAXD deficiency is broadening as our understanding of the disease expands and as more cases are identified. Here, we report the oldest known individual succumbing to NAXD-related neurometabolic crisis, at 32 years of age. The clinical deterioration and demise of this individual were likely triggered by mild head trauma. This patient had a novel homozygous NAXD variant [NM_001242882.1:c.441+3A>G:p.?] that induces the mis-splicing of the majority of NAXD transcripts, leaving only trace levels of canonically spliced NAXD mRNA, and protein levels below the detection threshold by proteomic analysis. Accumulation of damaged NADH, the substrate of NAXD, could be detected in the fibroblasts of the patient. In agreement with prior anecdotal reports in paediatric patients, niacin-based treatment also partly alleviated some clinical symptoms in this adult patient. The present study extends our understanding of NAXD deficiency by uncovering shared mitochondrial proteomic signatures between the adult and our previously reported paediatric NAXD cases, with reduced levels of respiratory complexes I and IV as well as the mitoribosome, and the upregulation of mitochondrial apoptotic pathways. Importantly, we highlight that head trauma in adults, in addition to paediatric fever or illness, may precipitate neurometabolic crises associated with pathogenic NAXD variants.

Changes in circulating microRNAs following head impacts in soccer.

AIM: To explore the short-term effects of accidental head impacts and repetitive headers on circulating microRNAs, accounting for the effects of high-intensity exercise alone. METHODS: Blood samples were collected from professional soccer players at rest. Repeat samples were drawn 1 h and 12 h after three conditions: (1) accidental head impacts in a match, (2) repetitive headers during training, and (3) high-intensity exercise. 89 samples were screened to detect microRNAs expressed after each exposure. Identified microRNAs were then validated in 98 samples to determine consistently deregulated microRNAs. Deregulated microRNAs were further explored using bioinformatics to identify target genes and characterize their involvement in biological pathways. RESULTS: Accidental head impacts led to deregulation of eight microRNAs that were unaffected by high-intensity exercise; target genes were linked to 12 specific signaling pathways, primarily regulating chromatin organization, Hedgehog and Wnt signaling. Repetitive headers led to deregulation of six microRNAs that were unaffected by high-intensity exercise; target genes were linked to one specific signaling pathway (TGF-ß). High-intensity exercise led to deregulation of seven microRNAs; target genes were linked to 31 specific signaling pathways. CONCLUSION: We identified microRNAs specific to accidental head impacts and repetitive headers in soccer, potentially being useful as brain injury biomarkers.

Circulating miRNAs expression as potential biomarkers of mild traumatic brain injury.

TBI is the main cause of death and disability in individuals aged 1-45 in Western countries. One of the main challenges of TBI at present is the lack of specific diagnostic biomarkers, especially for mild TBI (mTBI), which remains currently difficult to value in clinical practice. In this context MiRNAs may be important mediators of the profound molecular and cellular changes that occur after TBI in both the short and the long term. Recently, plasma miRNAs profiling in human TBI, have revealed dynamic temporal regulation of miRNA expression within the cortex. Aim of this study was to select a specific miRNAs panel for mTBI, by focusing the research on the prognostic meaning of miRNAs in the hours following the trauma, in order to be able to use this MIRNAs as potential biomarkers useful for monitoring the follow up of mild TBI. Serum levels of 17 miRNAs were measured by RT-quantitative polymerase chain reaction (qPCR) in 20 patients with mTBI at three different time-points (0 h, 24 h, 48 h) and in 10 controls. For 15 miRNAs we found a significant differences in the comparison among the three time points: for each of these miRNAs the values were greater at baseline and progressively reduced at 24 h and 48 h. These data allow us to consider the miRNAs included in panel as sensitive and specific biomarkers for mTBI, useful in monitoring the post-trauma period.

Factors influencing recovery from mild traumatic brain injury.

PRIMARY OBJECTIVE: This study determined whether initial GCS score, head CT results, cognitive performance on IMPACT testing, or APOE genotype most effectively predicted 1-month functional outcome after mild traumatic brain injury (mTBI). This study tested the hypotheses that participants with poor performance on initial cognitive testing and those with an APOEe4 genotype would exhibit a poorer 1-month recovery after mTBI. RESEARCH DESIGN: Regression analysis determined which independent variables were most effective in predicting 1-month GOS-E or DRS score. Independent t-test procedures determined whether cognitive recovery varied across APOEe4 carriers. METHODS AND PROCEDURES: 49 participants admitted to the hospital with mTBI received cognitive evaluation within 48 hours after injury and again one month later. DNA analysis provided participant APOE genotype. MAIN OUTCOMES AND RESULTS: Results showed that no study variables significantly predicted GOS-E or DRS scores, however, differences were identified when APOE groups were compared. Participants who were noncarriers of APOEe4 had significantly slower reaction times compared to APOEe4 carriers. Participants who were homozygous APOEe4 carriers had significantly lower instances of impulsivity than noncarriers. CONCLUSIONS: Further research is needed to understand how APOE allele status and performance on initial cognitive testing may influence short-term recovery after mTBI.

Saliva microRNA Biomarkers of Cumulative Concussion.

Recurrent concussions increase risk for persistent post-concussion symptoms, and may lead to chronic neurocognitive deficits. Little is known about the molecular pathways that contribute to persistent concussion symptoms. We hypothesized that salivary measurement of microribonucleic acids (miRNAs), a class of epitranscriptional molecules implicated in concussion pathophysiology, would provide insights about the molecular cascade resulting from recurrent concussions. This hypothesis was tested in a case-control study involving 13 former professional football athletes with a history of recurrent concussion, and 18 age/sex-matched peers. Molecules of interest were further validated in a cross-sectional study of 310 younger individuals with a history of no concussion (n = 230), a single concussion (n = 56), or recurrent concussions (n = 24). There was no difference in neurocognitive performance between the former professional athletes and their peers, or among younger individuals with varying concussion exposures. However, younger individuals without prior concussion outperformed peers with prior concussion on three balance assessments. Twenty salivary miRNAs differed (adj. p < 0.05) between former professional athletes and their peers. Two of these (miR-28-3p and miR-339-3p) demonstrated relationships (p < 0.05) with the number of prior concussions reported by younger individuals. miR-28-3p and miR-339-5p may play a role in the pathophysiologic mechanism involved in cumulative concussion effects.

Potential biomarkers to detect traumatic brain injury by the profiling of salivary extracellular vesicles.

Traumatic brain injury (TBI) is a common cause of death and acquired disability in adults and children. Identifying biomarkers for mild TBI (mTBI) that can predict functional impairments on neuropsychiatric and neurocognitive testing after head trauma is yet to be firmly established. Extracellular vesicles (EVs) are known to traffic from the brain to the oral cavity and can be detected in saliva. We hypothesize the genetic profile of salivary EVs in patients who have suffered head trauma will differ from normal healthy controls, thus constituting a unique expression signature for mTBI. We enrolled a total of 54 subjects including for saliva sampling, 23 controls with no history of head traumas, 16 patients enrolled from an outpatient concussion clinic, and 15 patients from the emergency department who had sustained a head trauma within 24 hr. We performed real-time PCR of the salivary EVs of the 54 subjects profiling 96 genes from the TaqMan Human Alzheimer's disease array. Real-time PCR analysis revealed 57 (15 genes, p < 0.05) upregulated genes in emergency department patients and 56 (14 genes, p < 0.05) upregulated genes in concussion clinic patients when compared with controls. Three genes were upregulated in both the emergency department patients and concussion clinic patients: CDC2, CSNK1A1, and CTSD ( p < 0.05). Our results demonstrate that salivary EVs gene expression can serve as a viable source of biomarkers for mTBI. This study shows multiple Alzheimer's disease genes present after an mTBI.

The functional roles of IGF-1 variants in the susceptibility and clinical outcomes of mild traumatic brain injury.

BACKGROUND: Insulin-like growth factor 1 (IGF-1) is an important pleiotropic hormone that exerts neuroprotective and neuroreparative effects after a brain injury. However, the roles of IGF-1 variants in mild traumatic brain injury (mTBI) are not yet fully understood. This study attempted to elucidate the effects of IGF-1 variants on the risk and neuropsychiatric outcomes of mTBI. METHODS: Based on 176 recruited mTBI patients and 1517 control subjects from the Taiwan Biobank project, we first compared the genotypic distributions of IGF-1 variants between the two groups. Then, we analyzed associations of IGF-1 variants with neuropsychiatric symptoms after mTBI, including anxiety, depression, dizziness, and sleep disturbances. Functional annotation of IGF-1 variants was also performed through bioinformatics databases. RESULTS: The minor allele of rs7136446 was over-represented in mTBI patients compared to community-based control subjects. Patients carrying minor alleles of rs7136446 and rs972936 showed more dizziness and multiple neuropsychiatric symptoms after brain injury. CONCLUSIONS: IGF-1 variants were associated with the risk and neuropsychiatric symptoms of mTBI. The findings highlight the important role of IGF-1 in the susceptibility and clinical outcomes of mTBI.

Hair follicle miRNAs: a novel biomarker for primary blast Induced-Mild traumatic brain injury.

CONTEXT: Due to the wide use of improvised explosive devices during modern warfare, primary blast-derived mild traumatic brain injury (mTBI) has become a major medical condition in the military. With minimal visually identifiable symptoms, an effective molecular biomarker system is desirable. OBJECTIVE: We assessed the potential of mammalian hair follicle miRNAs as an mTBI biomarker. MATERIALS AND METHODS: Due to their well-established roles in mTBI molecular pathology, the expression level of miR-183, miR-26a, miR-181c, miR-29a, miR-34a and miR-27b was determined using qRT-PCR in whisker hair follicles from rats subject to head-only exposure to a single-pulse shock wave. Based on established transcriptomics profiles, sub-network enrichment analysis (SNEA) was also conducted. RESULTS: The results revealed that molecular networks involving miR-183, miR-26a and miR-181c were enriched in multiple treatments, whereas sub-networks of miR-29a, miR-34a and miR-27b were unique to individual exposure groups. DISCUSSION: Our study showed that all six miRNAs were reflective of the mTBI signature involved in cellular responses. Noteworthy was that the decrease in the transcript levels of miR-181c was correlated with shockwave exposure severity. CONCLUSION: This study demonstrates for the first time that mammalian hair follicles are capable of housing miRNA biomarkers for TBI.

Self-Reported Mild Traumatic Brain Injuries in Relation to Rumination and Depressive Symptoms: Moderating Role of Sex Differences and a Brain-Derived Neurotrophic Factor Gene Polymorphism.

OBJECTIVE: Mild traumatic brain injuries (mTBIs) have frequently been associated with the emergence and persistence of depressive symptoms. However, the factors which contribute to the increased risk for depression after these head injuries remain unclear. Accordingly, we examined the relationship between frequency of self-reported mTBIs and current symptoms of depression and the mediating role of rumination and cognitive flexibility. We also examined whether these relations were moderated by sex differences and the presence of the Val66Met polymorphism in a gene coding for brain-derived neurotrophic factor (BDNF). DESIGN: Retrospective, cross-sectional. SETTING: Carleton University. PARTICIPANTS: Two hundred nineteen Carleton University undergraduate students. MAIN OUTCOME MEASURES: Cognitive flexibility as assessed by the Wisconsin Card Sorting Task (WCST); subtypes of rumination (Ruminative Response Scale; Treynor, Gonzalez, and Nolen-Hoeksema, 2003); depressive symptoms (Beck Depression Inventory; Beck, Ward, and Mendelson, 1961). RESULTS: Greater frequency of self-reported mTBIs was associated with more frequent depressive rumination among women, but not men, which was accompanied by elevated current depressive symptoms. In addition, among Met allele carriers of the BDNF polymorphism, but not those who were Val homozygotes, greater frequency of mTBIs was related to higher levels of brooding, which was accompanied by heightened depressive symptoms. Brain-derived neurotrophic factor genotype also moderated the relationship between self-reported mTBIs and cognitive flexibility in that more frequent mTBIs were associated with more perseverative errors on the WCST among Met carriers, but not Val homozygotes. CONCLUSIONS: The present findings raise the possibility that the evolution of depression after mTBIs may be dependant on a BDNF polymorphism and sex differences.

Sports-related Concussion - Genetic Factors.

Genetic biomarkers have been evaluated for validity in predicting risk for sports-related concussion as well as prognosticating recovery from this injury. Research results from predominantly small-scale pilot studies thus far are mixed and preliminary findings have not been adequately replicated. Currently, the use of such genetic biomarkers should be considered investigational and not for routine clinical use.

The association between BDNF Val66Met polymorphism and emotional symptoms after mild traumatic brain injury.

BACKGROUND: Brain-derived neurotrophic factor (BDNF) is one of the most abundant neurotrophins in the adult brain, and it plays important roles in modulating synaptic plasticity and synaptogenesis. This study attempted to elucidate the role of the BDNF variant rs6265 in emotional symptoms following mild traumatic brain injury (mTBI). METHODS: To investigate the association between BDNF Val66Met polymorphism (rs6265) and emotional symptoms in mTBI patients, we recruited 192 mTBI patients and evaluated their Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) scores in the first and sixth week after mTBI. RESULTS: The patients carrying the T allele of rs6265 had significantly higher BAI scores in the first week following mTBI. In addition, the patients carrying the T allele also showed higher scores of BDI in the first week. In the gender-specific subgroup analysis, the male patients carrying the T allele of rs6265 had higher scores of both BAI and BDI in the first and sixth week. Meanwhile, female patients carrying the T allele also had significantly higher scores of BDI in the first week following mTBI. CONCLUSIONS: This study provides evidence for the association between the BDNF variant rs6265 and emotional symptoms following mTBI.

Comprehensive assessment of shockwave intensity: Transcriptomic biomarker discovery for primary blast-induced mild traumatic brain injury using the mammalian hair follicle.

OBJECTIVE: Primary blast-induced mild traumatic brain injury (mTBI) is an injury experienced during modern warfare due to exposure to the pressure waves produced by the detonation of explosives. With virtually no apparent physical damage or symptoms presented, there is a need for more objective and accessible mTBI biomarkers posing minimal invasiveness risk. METHODS: We measured the transcriptomic sensitivity of the hair follicles in relation to the severity of primary blast-derived TBI. An Advanced Blast Simulator system was used to expose male rats to single pulse shock waves (intensities ranging from 15 to 30 psi) in a head-only fashion. Gene differential expression (DE) and gene set (GS) analyses were conducted in the rat whisker hair follicles and the whole blood samples. RESULTS: While shared cellular function, themes were found across the exposure groups, some gene sets under such themes were unique to the exposure conditions. Intensity-specific pathway enrichment patterns within shared GS themes were also identified. Furthermore, while exhibited shared pathways, the blood transcriptome showed substantially fewer enriched gene sets compared with the hair follicles across all exposure conditions. CONCLUSIONS: Accordingly, we demonstrate the potential of mammalian hair follicles serving as an additional source for biomarker discovery and for diagnosing mTBI with high accessibility.

Impact of age on acute post-TBI neuropathology in mice expressing humanized tau: a Chronic Effects of Neurotrauma Consortium Study.

OBJECTIVES: We hypothesized that polypathology is more severe in older than younger mice during the acute phase following repetitive mild traumatic brain injury (r-mTBI). METHODS: Young and aged male and female mice transgenic for human tau (hTau) were exposed to r-mTBI or a sham procedure. Twenty-four hours post-last injury, mouse brain tissue was immunostained for alterations in astrogliosis, microgliosis, tau pathology, and axonal injury. RESULTS: Quantitative analysis revealed a greater percent distribution of glial fibrillary acid protein and Iba-1 reactivity in the brains of all mice exposed to r-mTBI compared to sham controls. With respect to axonal injury, the number of amyloid precursor protein-positive profiles was increased in young vs aged mice post r-mTBI. An increase in tau immunoreactivity was found in young and aged injured male hTau mice. CONCLUSIONS: We report the first evidence in our model that r-mTBI precipitates a complex sequelae of events in aged vs young hTau mice at an acute time point, typified by an increase in phosphorylated tau and astroglisosis, and a diminished microgliosis response and axonal injury in aged mice. These findings suggest differential age-dependent effects in TBI pathobiology.

Genetic polymorphisms associated with the risk of concussion in 1056 college athletes: a multicentre prospective cohort study.

BACKGROUND/AIM: To evaluate the association of genetic polymorphisms APOE, APOE G-219T promoter, microtubule associated protein(MAPT)/tau exon 6 Ser53Pro, MAPT/tau Hist47Tyr, IL-6572 G/C and IL-6RAsp358Ala with the risk of concussion in college athletes. METHODS: A 23-centre prospective cohort study of 1056 college athletes with genotyping was completed between August 2003 and December 2012. All athletes completed baseline medical and concussion questionnaires, and post-concussion data were collected for athletes with a documented concussion. RESULTS: The study cohort consisted of 1056 athletes of mean±SD age 19.7±1.5 years, 89.3% male, 59.4% Caucasian, 35.0% African-American, 5.6% other race. The athletes participated in American football, soccer, basketball, softball, men's wrestling and club rugby. A total of 133 (12.1% prevalence) concussions occurred during an average surveillance of 3 years per athlete. We observed a significant positive association between IL-6R CC (p=0.001) and a negative association between APOE4 (p=0.03) and the risk of concussion. Unadjusted and adjusted logistic regression analysis showed a significant association between IL-6R CC and concussion (OR 3.48; 95% CI 1.58 to 7.65; p=0.002) and between the APOE4 allele and concussion (OR 0.61; 95% CI 0.38 to 0.96; p=0.04), which persisted after adjustment for confounders. CONCLUSIONS: IL-6R CC was associated with a three times greater concussion risk and APOE4 with a 40% lower risk.

The association between COMT rs4680 and 5-HTTLPR genotypes and concussion history in South African rugby union players.

The objective was to investigate the relationship between Catechol-O-methyltransferase (COMT) rs4680 and serotonin-transporter-linked polymorphic region (5-HTTLPR) genotypes with concussion history and personality traits. Rugby players ("all levels": n = 303), from high schools ("junior", n = 137), senior amateur, and professional teams ("senior", n = 166), completed a self-reported concussion history questionnaire, Cloninger's Tridimensional Personality Questionnaire, and donated a DNA sample. Participants were allocated into control (non-concussed, n = 140), case (all) (previous suspected or diagnosed concussions, n = 163), or case (diagnosed only) (previous diagnosed concussion, n = 140) groups. COMT rs4680 Val/Val genotypes were over-represented in controls in all levels (P = 0.013, OR:2.00, 95% CI:1.15-3.57) and in juniors (P = 0.003, OR:3.57, 95% CI:1.45-9.09). Junior Val/Val participants displayed increased "anticipatory worry" (P = 0.023). The 5-HTTLPR low expressing group was under-represented in controls when all levels were considered (P = 0.032; OR:2.02, 95% CI:1.05-3.90) and in juniors (P = 0.021; OR:3.36, 95% CI:1.16-9.72). Junior 5-HTTLPR low and intermediate expressing groups displayed decreased "harm avoidance" (P = 0.009), "anticipatory worry" (P = 0.041), and "fear of uncertainty" (P < 0.001). This study provides preliminary indications that personality associated genetic variants can influence concussion in rugby.

Inflammatory and apoptotic signalling pathways and concussion severity: a genetic association study.

The objective was to investigate the relationship between IL-1B rs16944, IL-6 rs1800795, and CASP8 rs3834129 genetic polymorphisms and concussion severity. Rugby players from high school, senior amateur, and professional teams completed a concussion severity questionnaire and donated a DNA sample. Participants (n = 163) were split into symptom severity groups around the median number and duration of symptoms. The frequency of participants with high symptom counts (more than five symptoms) increased across the IL-1B (C/C: 35%; C/T: 51%; T/T: 56%; P = 0.047) and the IL-6 (C/C: 31%; C/G: 44%; G/G: 58%; P = 0.027) genotypes. The C-C inferred interleukin allele construct frequency, created from combining the IL-1B and IL-6 genotype data, was lower in participants reporting a high symptom count (18%), compared to those with a low symptom count (fewer than six symptoms, 36%, P = 0.002). Similarly, the C-C inferred interleukin allele construct frequency was lower in those reporting prolonged symptom duration (more than one week, 16%), as opposed to short symptom duration (less than one week, 34%, P = 0.015). This study provides evidence of novel inflammatory pathway genetic associations with concussion severity, which supports the hypothesis implicating neuroinflammation in the development of concussion symptoms.