巨颌症SH-3BP-2基因突变检测及其蛋白表达

Gene mutation and expression of SH-3BP-2 in cherubism

目的检测巨颌症候选基因SH-3BP-2的突变类型及其蛋白表达情况，初步探讨SH-3BP-2突变与巨颌症病变细胞的关系。方法提取10例巨颌症病例（6例家族性，4例非家族性）的基因组DNA，用聚合酶链反应结合DNA直接测序方法检测SH-3BP-2基因的突变类型；应用酶组织化学和免疫组织化学法对8例巨颌症病变中多核巨细胞的性质进行鉴定，同时应用免疫组织化学方法检测SH-3BP-2蛋白在病变组织中的表达。结果发现6例存在SH-3BP-2基因第9外显子的单碱基错义突变，其中2例为G1520A，导致其编码的第420位氨基酸由甘氨酸（Gly）变为谷氨酸（Glu）；1例为G1505A，导致编码的第415位氨基酸由精氨酸（Arg）变为谷氨酰胺（Gln）；其余3例为G1505C，导致编码的第415位氨基酸由精氨酸（Arg）变为脯氨酸（Pro）。SH-3BP-2第3外显子除1例未扩增出PCR产物外，其余未检测到异常。8例石蜡标本病变组织中的所有多核巨细胞以及部分单核基质细胞胞质中均表达抗酒石酸酸性磷酸酶和降钙素受体以及SH-3BP-2蛋白。结论SH-3BP-2基因突变可能参与了病变组织中多核破骨样细胞的分化与成熟。

Objective To detect the mutation and expression of SH-3BP-2 in Chinese patients of cherubism and to investigate the possible relationship of gene mutation and multinucleated giant cells in lesions. Methods Genomic DNA was extracted from paraffin-embeded tissues and peripheral blood samples of 10 cases of cherubism（6 familial cherubisms and 4 sporadic cherubisms）. SH-3BP-2 mutations were detected by PCR-direct sequencing. The nature of muhinucleated giant cells in lesions was detected by enzyme histochemical staining and immunohistochemical staining using paraffin-embeded tissues sections. The SH-3BP-2 protein was detected by immunohistochemical staining. Results Three missense mutaions （G1520A, G1505A, G1505C ） in exon 9 of SH-3BP-2 were identified which led to 3 transitions （ Gly420G]u, Arg415Gln, Arg415Pro）. There were no abnormalities in exon 3 of SH-3BP-2 except 1 case which had not PCR products. The protein SH-3BP-2, the calcitonin receptor and the tartrate-resistant acid phosphatase were detected in the cytoplasm of all multinucleated giant cells and parts of monocaryon matrix cells in 8 paraffin-embeded samples. Conclusions The SH-3BP-2 mutation may participate in the differentiation and maturation of osteoclast-like cells in the lesion of cherubism.