Transcription factor 7-like 2 (TCF7L2) encodes a transcription factor involved in Wnt/β-catenin signaling pathway which encompasses an intronic single-nucleotide polymorphism (SNP, rs12255372) that has been associated with risk of Type 2 diabetes in linkage studies and genome-wide association studies [1-4] with potential modification by obesity [5]. Here, TCF7L2 is linked to obesity due to melanocortin 4 receptor deficiency.