Hereditary Multiple Osteochondromas, also known as hereditary multiple exostoses, is related to trichorhinophalangeal syndrome, type ii and exostoses, multiple, type i. An important gene associated with Hereditary Multiple Osteochondromas is EXT1 (Exostosin Glycosyltransferase 1), and among its related pathways/superpathways are Diseases of glycosylation and Chondroitin sulfate/dermatan sulfate metabolism. The drug Isotretinoin has been mentioned in the context of this disorder. Affiliated tissues include spinal cord and bone.