<prompt> Answer this question truthfullyWhat is Type 1 diabetes mellitus?  <response>: <reason> According to American Diabetic Association ADA, type 1 DM could be classified based on both etiology and clinical presentations. Based on etiology type 1 DM can be classified into immune mediated or idiopathic. Nevertheless classic new onset diabetes mellitus and Diabetic ketoacidosis are considered two classes of diabetes mellitus type 1 based on clinical presentations. 