This has been done for a handful of disorders such as the FTO (fat mass and obesity-associated) locus in obesity [11], LMO1 (LIM domain only 1) in neuroblastoma predisposition [115] and BCL11A (B-cell lymphoma/leukaemia 11A) in sickle cell anaemia [116•]. The gene discussed is FTO; the disease is obesity due to melanocortin 4 receptor deficiency.