APOE and obesity due to melanocortin 4 receptor deficiency: The majority of the main evidence includes oxidative-stress, inflammation, obesity, dysregulation of Apolipoprotein E (APOE), insulin degradation enzyme (IDE), Glucose Transporter type 4 (GLUT4), and Acetylcholinesterase (AChE), are linked to insulin resistance (Mittal and Katare, 2016).