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

线粒体脂肪酸β -氧化障碍（Mitochondrial fatty acid beta-oxidation disorders， FAOD）近年来引起了人们的广泛关注。我们调查了日本FAOD患者的实际情况，研究了FAOD患者的生化评价和分子分析。1)日本FAOD患者调查：采用问卷调查、文献调查和个人交流等方法，对1985 ~ 2000年间日本FAOD患者进行调查，共62例。CPT2缺乏症患者最多（14例），其次是2型戊二酸血症（12例）。儿童早期患者易患急性脑病样疾病，而儿童大龄或青少年期患者易患肌病。2)建立简化的GC/MS数据处理系统：在GC/MS有机酸血症筛查中，FAOD患者常表现为非糖尿病性二羧酸尿症。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。3)干血滤纸中游离脂肪酸的测定：对于fad的筛选，酰基肉碱串联质谱分析已成为流行的方法。串联质谱可能潜在地不能检测到这些疾病作为假阴性。建立了一种简便、灵敏的测定血液滤纸中游离脂肪酸含量的方法。4)利用培养细胞掺入ri标记脂肪酸检测FAOD：我们建立了掺入ri标记脂肪酸（棕榈酸酯和肉豆酸酯）检测FAOD的筛选系统，分析VLCAD缺乏症、GA2和CPT2缺乏症的细胞。5)日本VLCAD缺陷和GA2患者的分子分析：我们在5例VLCAD缺陷患者和3例GA2患者中发现了基因突变。在VLCAD缺乏症中，基因型/表型相关性明显，检测到的突变中存在温度敏感性。在GA2中，我们通过脉冲标记和DNA分析确定了两名患者中第一例etf - α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.