Professor Toni Cathomen is Director of the Institute for Transfusion Medicine & Gene Therapy at the Medical Center – University of Freiburg. Before his appointment in Freiburg, he held positions in San Diego, Berlin and Hannover. He has a strong interest in understanding on- and off-target effects of genome editors to ensure the safety of the edited (stem) cell preparations that are developed in his department to treat patients with chronic immunodeficiencies.