Analysis of GNAS mutations in cemento-ossifying fibromas and cemento-osseous dysplasias of the jaws

Objectives. It is well established that fibrous dysplasia (FD) is caused by mutations of the Arg(201) codon of the GNAS gene. However, the role of GNAS mutation in the pathogenesis of cement-osseous dysplasias (COD) and cemento-ossifying fibromas (COF) is not fully known. In this study, we examined COD and COF for mutations at the Arg(201) codon of the GNAS gene. Study design. The study sample included formalin-fixed, paraffin-embedded tissue blocks from 8 COF and 24 COD. We used 2 PCR-RFLP methods to detect mutations at the Arg(201) codon of the GNAS gene. Results. Mutations at the Arg(201) codon of the GNAS gene were not present in any of the COD and COF examined. Conclusions. GNAS mutations do not play a role in the pathogenesis of COD and COF. This highlights a clear molecular distinction between FD and other histologically similar fibro-osseous lesions of the jaws. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: 739-743)