From the results of our studies, IH upregulates the expression of POMC and CART mRNAs in neuronal cells and the expression of PYY, GLP-1, and NTS mRNAs in enteroendocrine cells, implying that IH itself may lead to loss of appetite in patients with SAS via the gut–brain axis (Figure 1). This evidence concerns the gene GCG and SATB2 associated disorder.