POMC and obesity due to melanocortin 4 receptor deficiency: Moreover, conditional deletion of Ngn3 specifically in the developing embryonic hypothalamus by using a Nkx2.1iCre transgenic mouse led in adulthood to a depletion of Pomc expression in arcuate neurons, a decrease in leptin sensitivity in ventral hypothalamic areas, and an associated obesity due to hyperphagia and reduced energy expenditure (Anthwal et al., 2013).