Armstrong Dawna Duncan
Department of Pathology, Baylor College of Medicine, Houston, Texas 77030, USA.
Ment Retard Dev Disabil Res Rev. 2002;8(2):72-6. doi: 10.1002/mrdd.10027.
Rett Syndrome is unlike any other pediatric neurologic disease, and its clinical-pathologic correlation can not be defined with standard histology techniques. Based on hypotheses suggested by careful clinical observations, the nervous system of the Rett child has been explored utilizing morphometry, golgi preparations, computerized tomography, magnetic resonance imaging, chemistry, immunocytochemistry, autoradiography, and molecular biologic techniques. From these many perspectives we conclude that Rett syndrome is not a typical degenerative disorder, storage disorder, nor the result of gross malformation, infectious or neoplastic processes. There remain regions of the brain that have not been studied in detail but the available data suggest that the neuropathology of Rett syndrome can be summarized as follows: the Rett brain is small for the age and the height of the patient; it does not become progressively smaller over three to four decades; it has small dendritic trees in pyramidal neurons of layers III and V in selected lobes (frontal, motor, and temporal); it has small neurons with an increased neuronal packing density; it has an immature expression of microtubular protein-2 and cyclooxygenase; it exhibits a changing pattern of neurotransmitter receptors with an apparent reduction in many neurotransmitters, possibly contributing to some symptomatology. A mutation in Mecp2 causes this unique disorder of brain development. Neuronal mosaicism for normal and mutated Mecp2 produces a consistent phenotype in the classic female patient and a small brain with some preserved islands of function, but with an inability to support hand use and speech. This paper summarizes our current observations about neuropathology of Rett syndrome. MRDD Research Reviews 2002;8:72-76.
雷特综合征不同于任何其他儿科神经系统疾病，其临床病理相关性无法用标准组织学技术来界定。基于仔细的临床观察所提出的假说，已运用形态测量学、高尔基染色法、计算机断层扫描、磁共振成像、化学、免疫细胞化学、放射自显影以及分子生物学技术对雷特患儿的神经系统进行了研究。从这些诸多角度来看，我们得出结论，雷特综合征并非典型的退行性疾病、贮积性疾病，也不是严重畸形、感染或肿瘤性病变的结果。大脑中仍有一些区域尚未得到详细研究，但现有数据表明，雷特综合征的神经病理学可总结如下：雷特患儿的大脑相对于其年龄和身高来说较小；在三到四十年间不会逐渐变小；在特定脑叶（额叶、运动区和颞叶）的III层和V层锥体细胞中树突树较小；神经元较小但神经元堆积密度增加；微管蛋白-2和环氧化酶的表达不成熟；神经递质受体呈现出变化模式，许多神经递质明显减少，这可能是某些症状的原因之一。Mecp2基因的突变导致了这种独特的大脑发育障碍。正常Mecp2基因和突变Mecp2基因的神经元镶嵌现象在典型的女性患者中产生了一致的表型，以及一个虽有一些功能保留岛但无法支持手部使用和言语功能的小大脑。本文总结了我们目前对雷特综合征神经病理学的观察结果。《MRDD研究评论》2002年；8：72 - 76。
