Keynote Speaker: Dr. Frank Sharp University of California at Davis, MIND Institute and Department of Neurology, USA Gene Expression in Blood as a window to Brain We were one of the first to hypothesize that gene expression in peripheral blood would change in response to disease in brain, muscle and other organs. As a proof of principle we showed that experimental ischemic stroke, status epilepticus, hemorrhage, hypoglycema and hypoxia produced unique gene expression profiles in blood of rats. In the last 10 years we have extended these studies to humans. Gene expression profiles have been discovered that are unique to ischemic stroke in humans, and that correlate with strokes that are caused by atheroemboli from the carotid and cardiac emboli. These profiles can be used to predict stroke and cause of stroke in individuals where the diagnosis is unclear or the cause is unclear. We have also applied this approach to individuals with Tourette’s syndrome, describing genes that change as a function of age that differ in controls compared to Tourette’s. These gene changes correlate with decreasing tics with increasing age. We have also discovered neurotransmitter genes expressed in blood that correlate with tic severity. Various medications have been shown to change gene expression in blood and in some cases correlate with the efficacy of treatment. These studies suggest that examining peripheral blood can be used to assess disease in brain at least in some cases, and holds the promise of being able to monitor therapy and perhaps predict efficacy of therapy.