Martinello F, Angelini C, Trevisan C P
Department of Neurologic and Psychiatric Sciences, University of Padua, Italy.
Eur Neurol. 1998 Jul;40(1):37-45. doi: 10.1159/000007954.
Merosin, the laminin alpha2 chain located on the surface of muscle fibers, has recently been shown to be absent in a subset of cases with the classical type of congenital muscular dystrophy (Cl-CMD). By immunocytochemistry and immunoblot analysis, using monoclonal antibodies to both the 80- and the 320-kDa fragments, the same protein was found to be only partially deficient in 3 of our cases. All these 3 patients were able to walk, with evidence of a mild to moderate muscle involvement, as opposed to the merosin-negative cases which are never ambulant because they are affected by severe muscular deficit. All of them also suffered from a late onset form of epilepsy, a clinical expression of brain involvement rarely described in cases with merosin-negative CMD. The 3 patients with CMD and partial merosin deficiency were investigated by brain MRI and pattern reversal visual evoked potentials (VEP) associated with electroretinography (ERG). The results were compared with those obtained by similar studies on 3 of our cases with complete merosin deficiency. In both types of patients, the neuroimaging evaluation showed supratentorial white matter changes, usually of moderate degree, irrespective of the amount of merosin detected in muscle. The VEP were normal in all the 3 cases with partial merosin deficiency, whereas they showed reduced amplitude or prolonged latency in all the 3 cases with the merosin-negative form. ERG was normal in all 6 cases. As a whole, our data indicate that leukoencephalopathy does not seem to distinguish between the two variants of Cl-CMD. On the other hand, a benign muscle involvement and normal VEP findings seem to distinguish CMD patients with partial merosin deficiency from those with complete deficiency of the same protein. Late onset epilepsy, evident in all our 3 cases with partial merosin deficiency, needs to be evaluated in a larger series of patients in order to be considered a characteristic of this variant of CMD.
肌纤蛋白，即位于肌纤维表面的层粘连蛋白α2链，最近发现在部分经典型先天性肌营养不良（Cl-CMD）病例中缺失。通过免疫细胞化学和免疫印迹分析，使用针对80 kDa和320 kDa片段的单克隆抗体，我们发现3例患者中同一蛋白仅部分缺乏。这3例患者均能行走，有轻度至中度肌肉受累的迹象，这与肌纤蛋白阴性的病例不同，后者因严重的肌肉缺陷而无法行走。他们还都患有迟发性癫痫，这是一种在肌纤蛋白阴性的CMD病例中很少描述的脑受累临床表现。对3例CMD且肌纤蛋白部分缺乏的患者进行了脑MRI检查以及与视网膜电图（ERG）相关的图形翻转视觉诱发电位（VEP）检查。将结果与我们对3例肌纤蛋白完全缺乏的病例进行类似研究所得到的结果进行比较。在这两类患者中，神经影像学评估均显示幕上白质改变，通常程度为中度，与肌肉中检测到的肌纤蛋白量无关。3例肌纤蛋白部分缺乏的病例VEP均正常，而3例肌纤蛋白阴性的病例VEP均显示波幅降低或潜伏期延长。6例患者的ERG均正常。总体而言，我们的数据表明白质脑病似乎无法区分Cl-CMD的两种变体。另一方面，良性肌肉受累和正常的VEP结果似乎可将肌纤蛋白部分缺乏的CMD患者与同一蛋白完全缺乏的患者区分开来。我们所有3例肌纤蛋白部分缺乏的病例中均出现的迟发性癫痫，需要在更多患者中进行评估，以便将其视为这种CMD变体的一个特征。
