FSD2 and obesity due to melanocortin 4 receptor deficiency: Several genes have been associated with obesity and obesity-related chronic diseases, including angiopoietin 4 (ANGPT4), RAR-related orphan receptor C (RORC), suppressor of cytokine signaling 3 (SOCS3), serine/threonine kinase 39 (STK39), fibronectin type III and SPRY domain containing 2 (FSD2), xylosyltransferase 1 (XYLT1), ATP binding cassette subfamily G member 1 (ABCG1), ankyrin repeat and SOCS box containing 2 (ASB2), and corticotropin releasing hormone receptor 2 (CRHR2) [34].