S-100β is a calcium binding protein found in astrocytes that has been shown to be present in TBI, however, it is not brain-specific and can be found in fatty tissue, bone and skin.79 There is some evidence to suggest it correlates with increased incidence of postconcussion syndrome (PCS), MRI changes and NP impairment,80 but equally strong evidence to disprove this.81 This variability renders S-100β of no clinical use in concussion. This evidence concerns the gene S100B and brain injury.