脂质沉积性肌病临床、病理和基因改变特点分析

目的报道一例脂质沉积性肌病的临床、病理和基因改变特点。方法先证者为33岁男性,亚急性起病,首发颈肌无力,随后出现咀嚼肌和四肢无力,肌酶明显升高,临床酷似多发性肌炎。血尿有机酸分析未见典型氨基酸、有机酸及脂肪酸代谢病改变,对患者进行了神经电生理、神经肌肉活检以及ETFA、ETFB、ETFDH基因检测。结果骨骼肌病理改变为肌纤维内出现大量脂肪滴沉积,伴随肌纤维坏死、再生。出现小组分布的累及两型的小角状萎缩肌纤维提示伴随神经源性损害。ETFA、ETFB基因检查基本正常,ETFDH基因第3外显子发现c.250GA(Ala84Thr)杂合突变。结论颈部肌肉无力可能是脂质沉积性肌病早期特点,需要引起重视。尿有机酸筛查正常并不能排除该疾病,进一步的肌肉活检和基因检测是诊断的金标准。多种酰基辅酶A脱氢酶缺乏症患者可以出现周围神经的损害,常染色体隐性遗传疾病相应基因的一个杂合突变难以解释,需要进一步研究。

The clinical,pathological and genetic characteristics of riboflavin - responsive lipid myopathy

Objective To summarize the clinical,pathological and genetic charactersitics of a case of riboflavin - responsive lipid myopa-thy. Methods The patient was a 33 year old man,whose initial syndrome was neck weakness,followed by the weakness of the masticatory muscle and limbs. It resembled the symptoms of polymyositis. Blood and urine organic acid analysis showed no typical changes of amino acids,organic acids and fatty acid metabolism disease. We performed nerve and muscle biopsy and ETFA,ETFB,ETFDH genetic testing. Results Muscle Bi-opsy study showed markedly increased lipid droplets in muscle fibers,accompanied by muscle fiber necrosis and regeneration. ETFA and ETFB ge-netic testing were normal,while the ETFDH gene analysis identified a c. 250G ﹥ A（Ala84Thr）heterozygous mutation. Conclusion Neck muscle weakness may be the early feature of lipid storage myopathy,which need to pay more attention. Normal urinary organic acid does not exclude the disease,further muscle biopsy and genetic testing are the gold standards for diagnosis. A heterozygous mutation for the autosomal recessive genetic disease is difficult to explain and requires further study.