It is therefore likely that combining both approaches; biochemical marker analysis and comparative genomics, with genome-wide association analysis and expression quantitative trait locus analysis, will be an effective combination to understand the tissue-specific regulation of the BDNF gene and how its misregulation, due to allelic variation, may contribute to obesity and/or pathological anxiety. This evidence concerns the gene BDNF and obesity due to melanocortin 4 receptor deficiency.