MED12 deficiency is a rare condition which includes the phenotypes of FG syndrome type 1 (FGS1, MIM: #305450), Lujan syndrome (LS, MIM: #309520), X-linked Ohdo syndrome (XLOS, MIM: #300895), non-specific intellectual disability (NSID), and Hardikar syndrome (HS, MIM: #301068) (Lyons, 1993). This evidence concerns the gene MED12 and histiocytic sarcoma.