Defective differentiation of thymocytes, reduction in CD4+ and CD8+ T cellsImproved striatum associated learning and memoryCocaine-induced early response gene expression and behavioural changeReduced adipogenesis, protection from obesity and insulin resistanceIncreased susceptibility to experimental autoimmune encephalomyelitisLack of development in brain ventricular zones and corpus callosum with intracerebral haemorrhages. Here, CD4 is linked to obesity due to melanocortin 4 receptor deficiency.