Ueda Yuka, Ando Atsushi, Nagata Taeko, Yanagida Hidehiko, Yagi Kazuro, Sugimoto Keisuke, Okada Mitsuru, Takemura Tsukasa
Department of Pediatrics, Kinki University School of Medicine, 377-2 Ohno-Higashi, 589-8511 Osaka-Sayama, Japan.
Pediatr Nephrol. 2004 Jan;19(1):107-10. doi: 10.1007/s00467-003-1318-7. Epub 2003 Nov 25.
Mitochondrial disorder is a relatively rare disease during childhood. Previous studies concluded that renal complications in this disease most often occur in patients with mitochondrial encephalomyopathies. We describe a boy with mitochondrial disease who presented with proteinuria while lacking neuromyopathy. Proteinuria was detected at the age of 6 years, including large amounts of low-molecular-weight proteins such as beta(2)- and alpha1-microglobulin. Renal functions were normal. Proximal tubular dysfunction and other renal manifestations were absent. Episodic neurologic problems such as migraine and nervous system diseases including epilepsy, depression, schizophrenia and amytrophic lateral sclerosis (ALS) were found in the boy's family members. Renal tubular basement membrane atrophy and interstitial fibrosis with mononuclear cell infiltration were observed. Ultrastructural examination showed mitochondria, mainly in the proximal tubules, which varied in size and had disoriented cristae. Mutation analysis using mitochondrial DNA (mtDNA) extracted from renal tissues demonstrated a A-->G point mutation at nucleotide position 3243 in the tRNA(Leu(UUR)) gene, while there was no mutation found in mtDNA extracted from peripheral leukocytes. Awareness among pediatricians of mitochondrial disorders, detection of low-molecular-weight proteinuria, renal ultrastructural examination and mutation analysis of mtDNA obtained from renal tissues could be important for early diagnosis of this disease.
线粒体疾病是儿童时期相对罕见的疾病。先前的研究得出结论，该疾病的肾脏并发症最常发生在线粒体脑肌病患者中。我们描述了一名患有线粒体疾病的男孩，他出现蛋白尿但无神经肌肉病变。蛋白尿在6岁时被检测到，包括大量低分子量蛋白质，如β2-微球蛋白和α1-微球蛋白。肾功能正常。无近端肾小管功能障碍及其他肾脏表现。在该男孩的家庭成员中发现了发作性神经系统问题，如偏头痛，以及包括癫痫、抑郁症、精神分裂症和肌萎缩侧索硬化症（ALS）在内的神经系统疾病。观察到肾小管基底膜萎缩和间质纤维化伴单核细胞浸润。超微结构检查显示线粒体主要存在于近端小管中，其大小各异且嵴排列紊乱。对从肾组织中提取的线粒体DNA（mtDNA）进行突变分析，发现在tRNA（Leu（UUR））基因的核苷酸位置3243处存在A→G点突变，而从外周血白细胞中提取的mtDNA未发现突变。儿科医生对线粒体疾病的认识、低分子量蛋白尿的检测、肾脏超微结构检查以及对从肾组织中获得的mtDNA进行突变分析，对于该疾病的早期诊断可能很重要。
