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 Arg²⁰¹ 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 Arg²⁰¹ 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 Arg²⁰¹ codon of the GNAS gene. Results: Mutations at the Arg²⁰¹ 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.