However, clinicians in Europe have monitored S100B to evaluate mTBI patients’ need for a head CT and to detect secondary injury progression.112 Continually elevated t-tau levels in preliminary studies of concussed athletes are associated with persistent post-concussive symptoms, whereas athletes with normal or only mildly elevated plasma tau resolve their symptoms and returned to full competition.206 Therefore, tau may be a potential biomarker to monitor recovery in athletes with TBI and could be used as a guide to allow them to safely return to play. The gene discussed is MAPT; the disease is concussion.