A Study Of42Cases Of Fibrous Dysplasia: Clinical Analysis And GNAS Gene Mutation Detection

Objectives: To analyse the clinical manifestation of fibrous dysplasia and to providereference for clinical diagnosis and treatment, meanwhile to understand its molecularetiology by performing GNAS gene mutation detectionMaterial and methods: a retrospective analysis was carried out based on clinical datafrom42cases of fibrous dysplasia patients (22male and20female), in which28casesunderwent GNAS genetic testing and16cases were confirmed by postoperative biopsy.Results: The age of patients ranges from1to75years old. The average age of onset(deduced by the time when patients showed symptoms or symptoms were revealed byphysical examination)was （26.6±17.4）and patients under40years old comprise78.6%of the whole cohort. Patients’chief complain included: local pain (16cases), local swellingand deformity (10cases), pathological fracture (14cases) and cafe-au-lait macules (8cases). Altogether119bones were damaged in the whole cohort and75were long bones,comprising63.0%, and the thighbone was most frequently damaged（25.2%）.18patientsshowed serum alkaline phosphatase over normal reference value, comprising52.9%(median value242U/L).4patients (11.8%) had serum inorganic phosphorus reduction.6patients (60%) showed B-CTX increase,3patients (23.1%) had parathyroid hormone overnormal reference value and1patient had hyperthyroidism. X-ray and CT examinationsshowed various lesions in pathogenic sites: cryptomere expansion, ground-glass-likechange, hyperplasia and sclerosis and the mixed type. ECT test showed typical signs ofradioisotope concentrating. GNAS genetic testing was performed on the peripheral bloodsample of27patients and two hotspot mutation sites were tested. But no genetic mutationwas detected.Conclusion: fibrous dysplasia is commonly seen in adolescents, often accompanied byostealgia, fracture and deformity, with thighbone mostly damaged. Some patients could have complications such as endocrine dysfunction and cafe-au-lait macules. Diagnosiscould be made with the help of CT, serum alkaline phosphatase test and B-CTX test.Further confirmation could be made via tissue biopsy. For treatment, the age of patientsand their symptoms should be considered. Surgery, medication or the combination of thesetwo therapies could be used according to different cases. Regular follow-up visits could beapplied to detect recurrence.