This protein and other members of its family (particularly TNF- α) have been implicated in diet-induced obesity from knock-out studies in mouse models.39 Following 8 weeks of treatment with EEN there was a significant increase in the weight Z-score of our participants; therefore the increase in TNFB could be explained by positive energy balance and weight gain. The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.