Carriers of the Thr54 allele in FABP2 gene have a twofold greater affinity for the absorption of long-chain fatty acids than those with the Ala54 allele (Agren et al., 2001), which supports the role of the FABP2 Ala54Thr polymorphism in the etiology of obesity and metabolic disorders. Here, FABP2 is linked to obesity due to melanocortin 4 receptor deficiency.