In addition, different pharmacological treatments may be tested on this zebrafish model, including phosphodiesterase inhibitors (PDEIs) and receptor agonists (such as setmelanotide, a novel MC4R agonist recently approved for treating certain monogenic and syndromic obesity forms), expediting the development of novel therapies for use in humans. The gene discussed is MC4R; the disease is obesity due to melanocortin 4 receptor deficiency.