1. Patients with type 1 diabetes mellitus as defined by the American Diabetes Association criteria or a history of ketoacidosis, or the patients are assessed by the study team as possibly having type 1 diabetes mellitus confirmed with the presence of at least one of the typical autoantibodies (insulin, GAD65, IA-2, ZnT8) AND a serum C-peptide level of <0.7 ng/mL.