Apolipoprotein E (APOE) ϵ4 Allele Is Associated with Increased Symptom Reporting Following Sports Concussion

Abstract

Exploring the relationship between genetic factors and outcome following brain injury has received increased attention in recent years. However, few studies have evaluated the influence of genes on specific sequelae of concussion. The purpose of this study was to determine how the ϵ4 allele of the apolipoprotein E (APOE) gene influences symptom expression following sports-related concussion. Participants included 42 collegiate athletes who underwent neuropsychological testing, including completion of the Post-Concussion Symptom Scale (PCSS), within 3 months after sustaining a concussion (73.8% were evaluated within 1 week). Athletes provided buccal samples that were analyzed to determine the make-up of their APOE genotype. Dependent variables included a total symptom score and four symptom clusters derived from the PCSS. Mann-Whitney U tests showed higher scores reported by athletes with the ϵ4 allele compared to those without it on the total symptom score and the physical and cognitive symptom clusters. Furthermore, logistic regression showed that the ϵ4 allele independently predicted those athletes who reported physical and cognitive symptoms following concussion. These findings illustrate that ϵ4+ athletes report greater symptomatology post-concussion than ϵ4- athletes, suggesting that the ϵ4 genotype may confer risk for poorer post-concussion outcome. (JINS, 2016, 22, 89-94).

Apolipoprotein E4 Polymorphism and Outcomes from Traumatic Brain Injury: A Living Systematic Review and Meta-Analysis

“…The effect size in the younger cohort was driven chiefly by those with moderate or severe injuries, and no APOE4 · TBI interaction could be detected in the oldest (60-64 years old) cohort. 57 Merritt and Arnett, 60 studying college athletes who had suffered a mild TBI in the last 3 months, showed an increase in post-concussive symptom burden among APOE4 carriers, and Banks and Bernick 59 found worse verbal memory performance among APOE4+ combat sports participants. This latter finding was nonetheless not associated with a decrease in hippocampal or thalamic volume, leaving the physiological underpinnings of APOE4 mediated cognitive impairment unclear.…”

Predictors of clinical recovery from concussion: a systematic review

“…Genetics,50 sex differences,1 16 18 51–53 younger age,1 7 12 38 54 neurodevelopmental factors such as attention deficit hyperactivity disorder (ADHD)55 56 or learning disability,57 personal57 or family history of migraine,58 or a personal14 58 or family history of mental health problems58 might also be predictors or effect modifiers of clinical recovery from concussion. Having a past concussion is a risk factor for having a future concussion,59 and having multiple past concussions is associated with having more physical, cognitive and emotional symptoms prior to participation in a sporting season 60 61.…”

Apolipoprotein E epsilon 4 (APOE‐ε4) genotype is associated with decreased 6‐month verbal memory performance after mild traumatic brain injury

“…However, an Indian cohort of mild‐to‐moderate TBI patients at 6 months showed no clear differences in neuropsychological test performance by APOE‐ ε 4 status (Pruthi et al., 2010). Reports of association between ε 4 carriers and postconcussional symptoms months to years postinjury also exist (Sundström et al., 2007; Merritt & Arnett, 2016; Pan et al., 2016). Population characteristics and TBI severity may contribute to the discrepancies in the current literature.…”