GPT and obesity due to melanocortin 4 receptor deficiency: Besides obesity, this volunteer also had severe fatty liver, as observed by ultrasonography, with concomitant markedly increased levels of serum concentrations of aspartate aminotransferase (122 U liter−1), alanine aminotransferase (97 U liter−1), and gamma-glutamyl transferase (168 U liter−1) (23).