The prevalence of type 2 diabetes mellitus (T2DM) has increased dramatically worldwide.1 Metformin is recommended as a first-line pharmacologic therapy for T2DM management,2 however, T2DM is a progressive disease that often requires a second-line agent, such as thiazolidinedione (TZD).2 Thiazolidinediones are ligands of peroxisome proliferator-activated receptor (PPAR) gamma, a member of the nuclear receptor superfamily of transcription factors.3 As PPAR gamma plays essential roles in improving glucose tolerance and insulin sensitivity, TZDs are referred as “insulin sensitizers.”4,5. This evidence concerns the gene INS and type 2 diabetes mellitus.