In 1995 the landmark NINDS trial randomised 624 patients with AIS to receive 0.9 mg/kg of IV r-tPA or placebo within three hours of stroke onset.8 Three months after treatment, 50% of patients in the treatment arm had minimal or no disability compared to 38% of patients in the placebo study arm: a 12% absolute improvement. The gene discussed is PLAT; the disease is Stroke.