The Neurovascular Diseases group at Vall d’Hebron Institute of Research (VHIR) has demonstrated the genetic component which is associated to the response to tissue plasminogen activator (t-PA) treatment in acute phase of ischemic stroke. This finding could modify the criteria for administrating this drug and allow clinicians to individualize the treatment more accurately, defining t-PA risk versus benefit in high-risk individuals. The results of this study improve the algorithms of response to this drug and suggest a predictive model combining clinical and genetic factors with more effectiveness. Wide interindividual variability exists in response to t-PA treatment in acute phase of ischemic stroke. Besides this drug is administrated to minimize adverse effects, between 2 and 5% of patients suffer brain hemorrhages, in some cases severe. In this study, VHIR researchers analyzed the highest series of patients treated with t-PA with the genotypic and phenotypic data collected, in order to find single nucleotide polymorphisms (SNPs). The prospective study used 140 SNPs from 97 candidate genes in more than 1,000 patients. “The results of the study have demonstrated that patients with a polymorphism in A2M gene are more likely to suffer brain hemorrhages and those with polymorphisms in factor XII are more associated with higher mortality rates after t-PA”, explains Dr. Israel Fernández-Cadenas, responsible of this study, together with Dr. Alberto del Río, from the Neurovascular Diseases group at VHIR.The study has been published in "http://onlinelibrary.wiley.com/doi/10.1002/ana.23664/abstract" "http://onlinelibrary.wiley.com/doi/10.1002/ana.23664/abstract" Annals of Neurology and is a collaborative work among centers as Fundació Docència, Recerca Mutuaterrassa, and groups that participated in the study GRECOS, from Hospital Clínic, Hospital de la Santa Creu i Sant Pau, Hospital del Mar, Hospital de Basurto and Hospital Dr. Josep Trueta, all of them with a vast data collected from patients.