CREB1 and obesity due to melanocortin 4 receptor deficiency: The long non‐coding RNA obesity‐related (Obr) promotes H3K27 acetylation and transcriptional upregulation of genes involved in lipid metabolism through its association with the Creb histone acetyltransferase complex, which includes the cAMP response element‐binding protein (Creb), CREB‐binding protein (Cbp), and p300.