Radioulnar Synostosis, also known as radio-ulnar synostosis type 1, is related to congenital radioulnar synostosis and 3mc syndrome. An important gene associated with Radioulnar Synostosis is MECOM (MDS1 And EVI1 Complex Locus), and among its related pathways/superpathways are Chondroitin sulfate/dermatan sulfate metabolism and Initial triggering of complement. Affiliated tissues include bone marrow and bone, and related phenotypes are radioulnar synostosis and limited pronation/supination of forearm