In agreement with such a possibility, heterozygous SOCS3 (SOCS3+/−) mice or mice with targeted invalidation of SOCS3 in the central nervous system (CNS) were protected against diet-induced obesity and associated insulin resistance (Howard et al., 2004; Mori et al., 2004; Kievit et al., 2006). The gene discussed is SOCS3; the disease is obesity due to melanocortin 4 receptor deficiency.