A systematic review and meta-analysis conducted by Blek and colleagues to assess the diagnostic and prognostic value of copeptin in patients with acute ischaemic stroke, found in most studies reviewed that the initial infarct volume in the brain as determined by a CT or MRI scan and copeptin have a positive correlation with a rise in the level of this biomarker. This can be explained by the association between the development of cerebral oedema (with subsequent release of AVP) following focal restriction of blood flow as seen in acute ischaemic stroke. The gene discussed is AVP; the disease is brain edema.