Cherubism: clinicopathologic study and mutational detection of c-Abl-binding SH3BP2 gene

Objectives: The latest genetic research has mapped cherubism (CBM) to chromosome 4p16.3. Point mutations in the gene encoding c-Abl-binding protein SH3BP2 are demonstrated. The aim of this study is to elucidate whether a mutation in SH3BP2 gene is detected in Chinese familial cherubism. The clinicopathologic feature is analyzed to clarify the nature of lesions from this study. Methods: Two cases of the aggressive form of cherubism were described in two Chinese families with unusual extremely extensive swelling in the bilateral mandible, typical pathological nature and apparent familial history. Mutation of SH3BP2 gene was detected by PCR and direct DNA sequencing for SH3BP2 gene was carried out in 5 affected and 2 unaffected with CBM within two families. Results: Mutational alteration was not detected at exon 1-13 or exon-intron boundaries of SH3BP2 gene in any of these 7 individuals. Clinical and radiographic examination manifested an outstanding overenlarged mandible and characteristic multilocular radiolucencies. Histopathological findings showed that varying numbers of multinucleated giant cells in a stroma of fibroblasts and the eosinophilic cuffing surrounding some vessels. Conclusion: Exon 9 in SH3BP2 gene is not the mutational hotspots of Chinese familial patients with CBM, and this gene does not seem to be involved in CBM pathogenesis. Cherubism should be diagnosed according to the familiar history, clinical, radiographic examination and histopathological findings.