Excitingly, they found that this impaired leptin responsiveness could be reversed in obese mice by pre-treating orally with a chemical chaperone to enhance ER function; thus giving rise to a novel class of leptin-sensitising, anti-obesity drugs targeting ER stress (Liu et al. 2015; Ozcan et al. 2009). The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.