FABP4 and obesity due to melanocortin 4 receptor deficiency: Transgenic mice overexpressing glycerol 3‐phosphate dehydrogenase and carrying ALBP promoter/enhancer‐reporter constructs were generated to study obesity mechanisms. Additionally, transgenic and gene knockout mice were used to identify mutations causing single‐gene obesity syndromes and for pharmaceutical drug development targeting human‐specific drug pathways.