Contrarily, previous child and adolescent studies showed elevated serum ALT levels were associated with higher BMI [14,15], fat mass index [15] and WC [14–16], and higher prevalence of central obesity [5,14], body fat proportion [5], and overweight and/or obesity [5,6,14,17] compared to subjects with serum ALT levels within the healthy range. Here, GPT is linked to obesity due to melanocortin 4 receptor deficiency.