Hiraki N, Udaka T, Yamamoto H, Kadokawa Y, Ohkubo J, Suzuki H
Department of Otorhinolaryngology, Hamamatsu Rosai Hospital, Hamamatsu, Japan.
J Laryngol Otol. 2010 Sep;124(9):1007-9. doi: 10.1017/S0022215110001477. Epub 2010 Jun 15.
We report a rare case of mitochondrial neurogastrointestinal encephalomyopathy with hearing loss.
A 46-year-old woman presented with a three-year history of progressive, bilateral hearing loss and tinnitus. She had been suffering from unexplained abdominal pain and diarrhoea for 20 years. When first seen, her otoscopic findings were normal, and pure tone audiometry showed mild and moderate hearing loss in her right and left ears, respectively. She also had: bilateral ophthalmoparesis, neck and limb muscle weakness, and hypoactive deep tendon reflexes on neurological examination; diffuse leukoencephalopathy on magnetic resonance imaging of the brain; and markedly reduced leukocyte thymidine phosphorylase activity. On the basis of these findings, the patient was diagnosed with mitochondrial neurogastrointestinal encephalomyopathy.
Mitochondrial neurogastrointestinal encephalomyopathy is an autosomal recessive disease caused by mutation of the thymidine phosphorylase gene, and is characterised by ophthalmoparesis, peripheral neuropathy, leukoencephalopathy, gastrointestinal symptoms and abnormal mitochondria in muscle cells. Current advances in genetic research may reveal a higher prevalence of mitochondrial disorders than had previously been thought. Otolaryngologists should be aware of mitochondrial neurogastrointestinal encephalomyopathy and other rare genetic disorders when managing patients with progressive hearing loss.
我们报告一例伴有听力损失的线粒体神经胃肠性脑肌病罕见病例。
一名46岁女性，有三年渐进性双侧听力损失和耳鸣病史。她有20年不明原因的腹痛和腹泻。初诊时，她的耳镜检查结果正常，纯音听力测定分别显示其右耳和左耳有轻度和中度听力损失。她还存在：双侧眼肌麻痹、颈部和肢体肌肉无力，以及神经系统检查时的腱反射减弱；脑部磁共振成像显示弥漫性白质脑病；白细胞胸苷磷酸化酶活性显著降低。基于这些发现，该患者被诊断为线粒体神经胃肠性脑肌病。
线粒体神经胃肠性脑肌病是一种由胸苷磷酸化酶基因突变引起的常染色体隐性疾病，其特征为眼肌麻痹、周围神经病变、白质脑病、胃肠道症状以及肌肉细胞中的线粒体异常。目前基因研究的进展可能显示线粒体疾病的患病率比之前认为的更高。耳鼻喉科医生在诊治进行性听力损失患者时应了解线粒体神经胃肠性脑肌病和其他罕见的遗传疾病。
