Qualitative research shows that people with type 1 diabetes increasingly expect closed-loop systems to be able to cope with atypical scenarios.8, -10 In response, some closed-loop systems, such as the CamAPS FX app, now include a personalizable user-initiated mode of operation, activation of which notifies the algorithm that insulin requirements are higher for a user-defined time period.11 This has the potential to improve usability, increase time in range, and reduce risk of hypoglycemia associated with standard manual correction doses. This evidence concerns the gene INS and type 1 diabetes mellitus.