Despite high CSF YKL-40 levels were found in sCJD and AD, increased YKL-40 levels have also been detected in other neurological and psychiatric conditions such as brain concussions [99], acute ischemic stroke [100], suicidal ideation [101] and bipolar disorder [102], underlining that astrocytic activation is not restricted to neurodegenerative conditions and that neuroinflammation may play a more prominent and common role in the etiology of neurological diseases. The gene discussed is CHI3L1; the disease is Alzheimer disease.