Ginjaar I B, Bakker E, den Dunnen J T, Wessels A, van Paassen M M, Kloosterman M D, Zubrzycka-Gaarn E E, Fischbeck K H, Moorman A F, van Ommen G J
Dept. of Human Genetics, Sylvius Laboratory, Leiden, The Netherlands.
Adv Exp Med Biol. 1990;280:17-23. doi: 10.1007/978-1-4684-5865-7_4.
An immunohistochemical study was carried out on a twelve-week old fetus, aborted for high risk of Duchenne muscular dystrophy. Southern and FIGE analysis showed an intragenic duplication in the DMD gene, which had previously resulted in a severe Duchenne phenotype in three relatives. Polyclonal antibodies directed against the NH2-terminal half of dystrophin showed a positive reaction an a similar distribution of dystrophin in the skeletal myotubes of a twelve-week old normal fetus and the affected fetus. In contrast, a polyclonal antibody directed against the COOH-terminus of dystrophin, i.e., distal to the mutation in this family, did only react with the myotubes of the normal fetus and not with those of the affected fetus. This indicates the presence of a truncated dystrophin in the affected fetus. Apparently at this stage, before binding of dystrophin to the sarcolemma, no distinction is made yet between normal and abnormal dystrophins. This implies that the potential to bind to the sarcolemma could be a major point of discrimination between normal and defective dystrophins. The truncated dystrophin will probably be degraded in a later stage during fetal development. So it appears that the use of dystrophin immunostaining to confirm high Duchenne risk abortions requires great caution. To prevent false-positive results, the combined use of NH2- and COOH-terminal antibodies is mandatory.
对一名因杜兴氏肌营养不良症高风险而流产的12周龄胎儿进行了免疫组织化学研究。Southern和FIGE分析显示DMD基因存在基因内重复，这在三名亲属中先前导致了严重的杜兴氏表型。针对肌营养不良蛋白NH2末端一半的多克隆抗体在12周龄正常胎儿和受影响胎儿的骨骼肌肌管中显示出阳性反应以及肌营养不良蛋白的相似分布。相比之下，针对肌营养不良蛋白COOH末端（即该家族突变远端）的多克隆抗体仅与正常胎儿的肌管发生反应，而不与受影响胎儿的肌管发生反应。这表明受影响胎儿中存在截短的肌营养不良蛋白。显然在这个阶段，在肌营养不良蛋白与肌膜结合之前，正常和异常的肌营养不良蛋白之间还没有区别。这意味着与肌膜结合的潜力可能是正常和有缺陷的肌营养不良蛋白之间的主要区别点。截短的肌营养不良蛋白可能会在胎儿发育的后期阶段被降解。因此，似乎使用肌营养不良蛋白免疫染色来确认杜兴氏高风险流产需要非常谨慎。为防止假阳性结果，必须联合使用NH2末端和COOH末端抗体。
