<i>Background and Objectives</i>: The pathogenesis of liver steatosis is associated with obesity and systemic inflammation, particularly in subjects with body mass index (BMI) above 40 kg/m<sup>2</sup> and altered serum levels of tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10). The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.