GDF15 and obesity due to melanocortin 4 receptor deficiency: GDF15 is a well‐known biomarker for metabolic diseases, with higher GDF15 levels corresponding to metabolic diseases such as atherosclerosis, cardiomyopathies, obesity, insulin resistance, and chronic kidney diseases (Adela & Banerjee, 2015; Berezin, 2016; Hong et al., 2014).