The exact number of drug discovery initiatives targeting FTO to treat obesity or type 2 diabetes is unknown to us, but the findings of Smemo et al. (2014)– obtained by combining experimental data from several animal models including zebrafish – illustrate the need of carrying out detailed genetic functional studies (i.e., functional genomics) before entering costly drug discovery programs. The gene discussed is FTO; the disease is obesity due to melanocortin 4 receptor deficiency.