Study on biochemical and molecular evoluation for mitochondrial β-oxidation defects

线粒体脂肪酸β-氧化障碍（FAOD）是近年来备受关注的疾病。我们调查了日本FAOD患者的实际情况，并对FAOD患者的生化评估和分子分析进行了研究。1）日本FAOD患者的调查：我们在1985年至2000年期间，通过问卷调查、文献和个人交流，发现了62例日本FAOD患者。CPT 2缺乏症患者数量最多（14例），其次是2型谷氨酸血症（12例）。儿童早期的患者倾向于急性脑病样疾病，而年龄较大的儿童或青少年的患者倾向于肌病性疾病。2）建立简化的GC/MS数据处理系统：在有机酸血症的GC/MS筛查中，FAOD患者常表现为非溶血性二羧酸尿症。我们建立了一个基于个人计算机的自动代谢分析和诊断系统。测量干血滤纸中的游离脂肪酸：对于FAOD的筛选，通过串联MS进行酰基肉毒碱分析已变得流行。串联MS可能无法检测到假阴性的此类疾病。我们建立了一种简单、灵敏的方法来测量血液滤纸中的血液游离脂肪酸水平。4）通过使用培养的细胞掺入RI标记的脂肪酸来检测FAOD：我们通过掺入RI标记的脂肪酸，包括棕榈酸和肉豆蔻酸，分析VLCAD缺陷的细胞，GA 2和CPT 2缺陷。5）日本VLCAD缺陷和GA 2患者的分子分析：我们在5名VLCAD缺陷患者和3名GA 2患者中鉴定了基因突变。在VLCAD缺陷中，基因型/表型相关性明显，并且在检测到的突变中观察到温度敏感性。在GA 2中，我们通过脉冲标记和DNA分析在两名患者中发现了日本首例ETF-alpha亚基缺乏症。

Mitochondrial fatty acid beta-oxidation disorders (FAOD) has atracted attention recently. We investigated the acutual situation of Japanese patients with FAOD, and studied the biochemical evaluation and molecular analysis of FAOD patients.1) Survey of Japanese patients with FAOD : We found 62 Japanese patients with FAOD during the period between 1985 to 2000, using questionnaires, literatures and personal communications. The number of patients was largest in CPT2 deficiency (14), second was glutaric acidemia type 2 (12). The patients in early childhood tend to have acute encephalopathy-like illness, whereas patients in older childhood or adolescence did myopathic illness.2) Establishment of a simplified GC/MS data processing system : FAOD patients often show nonkletotic dicarboxylic aciduria in organic acidemia screening using GC/MS.We established a personal computer-based system of automated metabolic profiling and diagnosis.3) Measurement of free fatty acids in dried blood filter paper : For the screening of FAOD, acylcarnitine analysis by tandem MS has become popular. Tandem MS may potentially fail to detect such disorders as a false-negative. We established a simplified, sensitive method to measure the blood free fatty acid levels in blood filter paper.4) Detection of FAOD by incorporation of RI-labeled fatty acids using cultured cells : We established a screening system for FAOD by incorporation of RI-labeled fatty acids, including palmitate and myristate, analyzing cells from VLCAD deficiency, GA2 and CPT2 deficiency.5) Molecular analysis of Japanese patients with VLCAD deficiency and GA2 : We identified genetic mutations in five VLCAD deficient patients and three GA2 patients. In VLCAD deficiency, the genotype/phenotype correlation was apparent and the temperature sesitivity was seen among mutations detected. In GA2, we identified the first Japanese case of ETF-alpha subunit deficiency in two patients by pulse labeling and DNA analysis.