In this ancillary study to the Restoring Insulin SEcretion (RISE) Study, a multi-site national clinical trial, we investigated the prevalence of and association with β-cell dysfunction of islet reactive T cells and autoantibodies to the 65 kDa glutamic acid decarboxylase antigen (GADA) in adults with impaired glucose tolerance (IGT), and in treatment naïve adults with recently diagnosed T2D. This evidence concerns the gene INS and type 2 diabetes mellitus.