The mechanism of steatogenic action of CLA is clearly mediated by the increased expression of lipogenetic proteins: the up-regulation of ketohexokinase correlates with steatosis and obesity, while the up-regulation of the peroxisomal acyl-coenzyme A oxidase-1 suggests an increase in fatty acid β-oxidation in peroxisomes. The gene discussed is ACOX1; the disease is obesity due to melanocortin 4 receptor deficiency.