Eisenschenk S, Triggs W J, Pearl G S, Rojiani A M
Department of Neurology, University of Florida College of Medicine, Gainesville, Florida, USA.
Ann Clin Lab Sci. 2001 Apr;31(2):140-6.
The primary genetic abnormality in myotonic dystrophy (DM) is an expansion of the CTG trinucleotide repeat on chromosome 19q. Recently, patients with similar clinical features, but without this genetic alteration, have been designated as proximal myotonic myopathy (PROMM). We describe two additional cases of PROMM, both of whom presented with clinical features suggestive of myotonic dystrophy. The patients had electromyographic (EMG) evidence of myotonia, normal cardiac evaluation, and no cataracts. Genetic analysis of peripheral blood leukocytes revealed no expansion of the trinucleotide repeat by polymerase chain reaction (PCR) and Southern blot analysis. Muscle biopsies in both cases were significant with features suggestive of myotonic dystrophy, such as large numbers of fibers containing multiple internal nuclei, occasional nuclear chains, and fiber atrophy, although sarcoplasmic masses and ring fibers were absent. These cases illustrate the clinical and neuropathologic findings of PROMM and underline the importance of correlating these aspects with genetic studies in patients with myotonic muscle disorders.
强直性肌营养不良（DM）的主要基因异常是19号染色体上CTG三核苷酸重复序列的扩增。最近，具有相似临床特征但无此基因改变的患者被命名为近端强直性肌病（PROMM）。我们描述了另外两例PROMM病例，这两名患者均表现出提示强直性肌营养不良的临床特征。患者有肌强直的肌电图（EMG）证据、心脏评估正常且无白内障。外周血白细胞的基因分析显示，通过聚合酶链反应（PCR）和Southern印迹分析，三核苷酸重复序列无扩增。两例患者的肌肉活检均有显著表现，提示强直性肌营养不良，如大量含有多个内部核的纤维、偶尔的核链和纤维萎缩，尽管没有肌浆块和环形纤维。这些病例说明了PROMM的临床和神经病理学发现，并强调了将这些方面与强直性肌病患者的基因研究相关联的重要性。
