I have read with interest the article titled, ‘Educational program for patients with type-1 diabetes mellitus receiving free monthly supplies of insulin improves knowledge and attitude, but not adherence,’ Vimalavathini et al.[1] The authors mention in the second paragraph of introduction, “When a patient does not respond to an appropriately prescribed medicine, the reasons could be drug or patient-related factors”. This evidence concerns the gene INS and type 1 diabetes mellitus.