She was the principal investigator leading the successful gene therapy trial for SCID patients who lack an enzyme critical to DNA synthesis (ADA-SCID), which has received European Commission approval to market under the name of Strimvelis. Under her direction, the San Raffaele Scientific Institute has been seminal in showing the efficacy of gene therapy for otherwise untreatable inherited metabolic diseases and primary immunodeficiencies.

Dr. Roncarolo established the Stanford Center for Definitive and Curative Medicine to cure patients with currently incurable diseases through the development of innovative stem cell-and gene-based therapies.