CDKN1A and type 2 diabetes mellitus: The genes septin-9 (Sept9), cyclin-dependent kinase inhibitor 1A (Cdkn1a), and phosphodiesterase-7B (Pde7b) were selected based on their potential role in islet function and DM, along with their differential DNA methylation in multiple CpG sites and differential expression in T2DM islets.