INS and obesity due to melanocortin 4 receptor deficiency: As the n-3 FA/FFAR4 complex plays an important role in insulin sensitivity and islet function, and FFAR4 dysfunction was shown to be associated with insulin resistance, an obesity-related symptom of metabolic disorders, it becomes relevant to verify whether genetic variations within FFAR4 contribute to the inter-individual variability observed in insulin-related traits [9,16,18,19].