Increased levels of tau have been reported in the context of dementia, brain injury (Zetterberg 2016, Mattson 2017), cerebral concussion (Shahim 2014, Zetterberg 2016) and boxing (Neselius 2012, Zetterberg 2006), but also after less evident neuronal trauma as protracted apnea (Gren 2016) and uneventful anaesthesia (Evered 2018). The gene discussed is MAPT; the disease is brain injury.