TMSB4X and obesity due to melanocortin 4 receptor deficiency: Other genes that are closely related to lipid metabolism and obesity by signal transduction or regulation of transcription were also highly expressed: prosaposin (PSAP), retinol binding protein 7 (RBP7), retinoic acid receptor responder, IGFBP 7, thymosin beta 4, BMP7, superoxide dismutase 2 and annexin A5.