MSTN and obesity due to melanocortin 4 receptor deficiency: The direct relationship of myostatin and fat mass (that was independent of age or cirrhosis) was observed when myostatin was compared with crude data of fat mass at the right leg, left leg, and trunk; when myostatin was compared with fat at lower limbs; when myostatin was compared with the obesity criterion according to BMI and also when it was compared with the OSA criterion for obesity (although in this case the relation of OSA with age was more marked); and with the ratio total fat mass/total lean mass.