Vengalil Seena, Preethish-Kumar Veeramani, Polavarapu Kiran, Christopher Rita, Gayathri Narayanappa, Natarajan Archana, Manjunath Mahadevappa, Nashi Saraswati, Prasad Chandrajit, Nalini Atchayaram
Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India.
Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India; Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences, Bangalore 560029, India.
Neuromuscul Disord. 2017 Nov;27(11):986-996. doi: 10.1016/j.nmd.2017.08.004. Epub 2017 Aug 24.
Fatty acid oxidation disorders presenting as primary myopathy is relatively rare and also diagnostically challenging. Its association with "dropped head syndrome" is reported till date in single cases of carnitine deficiency and multiple acyl CoA dehydrogenase deficiency (MADD).We studied nineteen cases of primary progressive myopathy confirmed to have fatty acid oxidation defects by Tandem Mass Spectrometry. The detailed clinical, muscle histopathology, tandem mass spectrometry and muscle magnetic resonance imaging (MRI) findings are presented here. The fatty acid oxidation defects identified were sub-grouped into: medium chain acyl CoA dehydrogenase deficiency (MCAD) = 4; very long chain acyl CoA dehydrogenase deficiency (VLCAD) = 7; MADD = 6; carnitine uptake defect and short chain acyl CoA dehydrogenase (SCAD) deficiency = 1 each. The age at onset for MCAD, VLCAD and MADD ranged from 11.5 to 15, 8 to 17 and 10 to 38 years respectively. The patients with carnitine uptake defect and SCAD had onset at 29 and 15 years of age. The dominant symptoms were exertion induced myalgia and progressive proximal limb weakness in all. 12/19 (63.2%) had classical dropped head syndrome. Ptosis and bulbar weakness were present in a few cases. This study emphasizes that fatty acid oxidation disorders presenting as primary myopathy are probably under diagnosed and should be entertained in the differential diagnosis of acute or chronic limb girdle syndromes. Hitherto, unreported we describe "dropped head syndrome" as a prominent phenomenon in MCAD and VLCAD. The presence of ptosis and bulbar weakness in fatty acid oxidation defects expands the clinical spectrum.
表现为原发性肌病的脂肪酸氧化障碍相对罕见，诊断也具有挑战性。迄今为止，仅在单例肉碱缺乏症和多酰基辅酶A脱氢酶缺乏症（MADD）中报道过其与“垂头综合征”的关联。我们研究了19例经串联质谱法确诊存在脂肪酸氧化缺陷的原发性进行性肌病患者。本文呈现了详细的临床、肌肉组织病理学、串联质谱及肌肉磁共振成像（MRI）结果。所确定的脂肪酸氧化缺陷被分为以下亚组：中链酰基辅酶A脱氢酶缺乏症（MCAD）=4例；极长链酰基辅酶A脱氢酶缺乏症（VLCAD）=7例；MADD=6例；肉碱摄取缺陷和短链酰基辅酶A脱氢酶（SCAD）缺乏症各1例。MCAD、VLCAD和MADD的发病年龄分别为11.5至15岁、8至17岁和10至38岁。肉碱摄取缺陷和SCAD患者的发病年龄分别为29岁和15岁。主要症状均为运动诱发的肌痛和进行性近端肢体无力。12/19（63.2%）患者出现典型的垂头综合征。少数病例存在上睑下垂和延髓肌无力。本研究强调，表现为原发性肌病的脂肪酸氧化障碍可能未得到充分诊断，在急性或慢性肢带综合征的鉴别诊断中应考虑到。此前未报道过，我们描述“垂头综合征”在MCAD和VLCAD中是一种突出现象。脂肪酸氧化缺陷中出现上睑下垂和延髓肌无力扩展了临床谱。
