Kolodny E H
Department of Neurology, New York University School of Medicine, NY 20016.
Curr Opin Neurol Neurosurg. 1993 Jun;6(3):379-86.
The myelin membrane is essential for rapid conduction of nerve impulses through the central nervous system. Failure of myelination--dysmyelination--may arise through several mechanisms. The synthesis of a particular myelin protein can be defective, as occurs for proteolipid protein in Pelizaeus-Merzbacher disease and for myelin basic protein in the 18q- syndrome. Delay in myelination with a more generalized diminution in white matter is characteristic of many inherited metabolic diseases, including galactosemia, pyridoxine-dependent seizure disorder, glutaric aciduria type 1, and infantile Refsum disease. Demyelination or breakdown in myelin is characteristic of metachromatic leukodystrophy, Krabbe disease, mitochondrial disorders, adrenoleukodystrophy, Canavan disease, Alexander disease, and orthochromatic leukodystrophy. A fourth category is reserved for malformation syndromes. These include Cockayne, Fukuyama, Walker-Warburg, and Angelman syndromes. Demyelination also occurs in HIV-infected individuals with central nervous system findings and in multiple sclerosis. Much of the evidence for leukodystrophy in these disorders comes from neuroimaging. Some of these disorders are treatable.
髓鞘膜对于神经冲动在中枢神经系统中的快速传导至关重要。髓鞘形成失败——即髓鞘形成异常——可能通过多种机制产生。特定髓鞘蛋白的合成可能存在缺陷，如佩利措伊斯-梅茨巴赫病中的蛋白脂蛋白以及18q-综合征中的髓鞘碱性蛋白。许多遗传性代谢疾病的特征是髓鞘形成延迟且白质普遍减少，包括半乳糖血症、维生素B6依赖型癫痫症、戊二酸尿症1型和婴儿型Refsum病。脱髓鞘或髓鞘破坏是异染性脑白质营养不良、克拉伯病、线粒体疾病、肾上腺脑白质营养不良、卡纳万病、亚历山大病和正染性脑白质营养不良的特征。第四类是畸形综合征。这些包括科凯恩综合征、福山综合征、沃克-沃尔堡综合征和安吉尔曼综合征。脱髓鞘也发生在有中枢神经系统表现的HIV感染者和多发性硬化症患者中。这些疾病中脑白质营养不良的许多证据来自神经影像学检查。其中一些疾病是可治疗的。
