Division of Molecular Pathology, Department of Scientific Laboratories, Armed Forces Institute of Pathology, Washington, DC 20306, USA.
J Mol Diagn. 2011 Mar;13(2):137-42. doi: 10.1016/j.jmoldx.2010.10.003.
Benign fibro-osseous lesions (BFOLs) frequently display overlapping histological features. The differentiation of fibrous dysplasia (FD) from other BFOLs can be difficult, even for experienced orthopedic pathologists. Accurately distinguishing FD from other BFOLs may have significant clinical and treatment implications. A somatic mutation in gene GNAS encoding the α subunit of the G protein (Gsα) involving the codon corresponding to Arg 201 has been identified in FD and is specifically absent in other BFOLs. We have developed a quantitative assay by pyrosequencing that has a detection sensitivity of 95%. The test allows the identification of the two most common types of mutation (Arg→His and Arg→Cys) in a single reaction, with the ability to analyze other rare mutations. Of the 24 FD cases in this series, 23 (96%) were positive for GNAS/Gsα mutation. Nineteen of 23 positive cases exhibited a G→A mutation (Arg→His), whereas four had a C→T mutation (Arg→Cys). One of three BFOL, not otherwise specified cases was positive for G→A mutation. None of the osteofibrous dysplasia, ossifying fibromas, or other bone lesions were positive for this mutation. Our experience is that pyrosequencing is an easy and accurate quantification method for Gsα mutation detection in fibrous dysplasia. Mutation analysis of the Gsα by pyrosequencing has significant potential for improving discrimination between FD and other BFOLs in problematic cases.
良性纤维骨病变 (BFOLs) 常表现出重叠的组织学特征。纤维发育不良 (FD) 与其他 BFOLs 的鉴别可能很困难，即使是经验丰富的骨科病理学家也是如此。准确地区分 FD 与其他 BFOLs 可能具有重要的临床和治疗意义。在 FD 中已鉴定出编码 G 蛋白 (Gsα)α 亚单位的基因 GNAS 中的体细胞突变，涉及与精氨酸 201 对应的密码子，而在其他 BFOLs 中则特异性缺失。我们已经开发了一种通过焦磷酸测序进行的定量测定法，其检测灵敏度为 95%。该测试允许在单个反应中鉴定两种最常见的突变类型（精氨酸→组氨酸和精氨酸→半胱氨酸），并能够分析其他罕见的突变。在本系列的 24 例 FD 病例中，23 例（96%） GNAS/Gsα 突变阳性。23 例阳性病例中有 19 例显示 G→A 突变（精氨酸→组氨酸），而 4 例显示 C→T 突变（精氨酸→半胱氨酸）。三个非特指 BFOL 中的一个病例 G→A 突变阳性。骨纤维发育不良、骨化纤维瘤或其他骨病变均未检测到该突变。我们的经验是，焦磷酸测序是一种用于纤维发育不良中 Gsα 突变检测的简单且准确的定量方法。通过焦磷酸测序对 Gsα 的突变分析在有问题的病例中具有提高 FD 与其他 BFOLs 之间区分的显著潜力。
