IGFBP1 and obesity due to melanocortin 4 receptor deficiency: Previous studies have described the potential impact of obesity—along with associated hepatic steatosis, decreased ghrelin levels, and hyperinsulinemia affecting IGF-1 binding protein (IGF-BP) concentrations—on the reduction of IGF-1 levels, particularly in individuals with a BMI in the range of 30–35 kg/m2 [42].