Casar-Borota Olivera, Jacobsson Johan, Libelius Rolf, Oldfors Carola Hedberg, Malfatti Edoardo, Romero Norma Beatriz, Oldfors Anders
Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden; Department of Clinical Pathology and Cytology, Uppsala University Hospital, Uppsala, Sweden.
Institution of Pharmacology and Clinical Neuroscience, Section of Neurology, Umeå University, Umeå, Sweden.
Neuromuscul Disord. 2015 Apr;25(4):345-8. doi: 10.1016/j.nmd.2015.01.001. Epub 2015 Jan 13.
Nuclear centralisation and internalisation, sarcoplasmic radiating strands and type 1 muscle fibre predominance and hypotrophy characterise dynamin-2 (DNM2) associated centronuclear myopathy, whereas necklace fibres are typically seen in late onset myotubularin-1 (MTM1)-related myopathy. We report a woman with unilateral symptoms probably related to brachial plexus neuritis. Electromyography revealed localised neuropathic and generalised myopathic abnormalities. The typical features of DNM2 centronuclear myopathy with additional necklace fibres were found in the muscle biopsy. Sequencing of the DNM2 and MTM1 genes revealed a novel heterozygous missense mutation in exon 18 of the DNM2, leading to replacement of highly conserved proline at position 647 by arginine. The muscle symptoms have not progressed during the 3-year follow-up. However, the patient has developed bilateral subtle lens opacities. Our findings support the concept that necklace fibres may occasionally be found in DNM2-related myopathy, possibly indicating a common pathogenic mechanism in DNM2 and MTM1 associated centronuclear myopathy.
核集中化与内化、肌浆放射状纤维、1型肌纤维优势及萎缩是动力蛋白2（DNM2）相关中央核性肌病的特征，而项链样纤维通常见于晚发型肌管素-1（MTM1）相关肌病。我们报告了一名有单侧症状的女性，可能与臂丛神经炎有关。肌电图显示局部神经性和全身性肌病异常。肌肉活检发现了具有额外项链样纤维的DNM2中央核性肌病的典型特征。对DNM2和MTM1基因进行测序，发现在DNM2第18外显子中有一个新的杂合错义突变，导致第647位高度保守的脯氨酸被精氨酸取代。在3年的随访期间，肌肉症状未进展。然而，该患者出现了双侧轻微晶状体混浊。我们的研究结果支持这样一种观点：在DNM2相关肌病中偶尔可能发现项链样纤维，这可能表明DNM2和MTM1相关中央核性肌病存在共同的致病机制。
