IRX3 and obesity due to melanocortin 4 receptor deficiency: Recently, it was reported that rs1421085 T-to-C intron of the well-known obesity-associated FTO gene, disrupts a conserved motif for the ARID5B repressor, which leads to derepression of a potent preadipocyte enhancer and a doubling of the transcription factors IRX3 and IRX5 expression during early adipocyte differentiation.