目的 建立应用成纤维细胞体外培养结合串联质谱酰基肉碱谱分析的诊断方法,诊断并鉴别不同的遗传性线粒体脂肪酸β-氧化代谢障碍病.方法 取健康对照标本6例和已确诊的遗传性线粒体脂肪酸β-氧化代谢障碍病患儿标本14例,包括SCAD(n=1)、MCAD(n=3)、VLCAD(n =3)、CPT-Ⅱ(n =2)、MTP(n=2)、MCD(n =2)和CACT(n=1)等酶的缺陷共7种病症.以棕榈酸(C16酸)为培养溶媒底物,成纤维细胞株37℃持续培养96h后,应用串联质谱分析相应培养液中的酰基肉碱谱并计算比较相应结果,行诊断和鉴别诊断.结果 所有病人的C2均显著低于对照组,其它酰基肉碱的浓度在不同病种的表现各不相同,SCADD呈现C4异常增高；MCADD显示C8的特异性增高；VLCADD则以C12的异常增高为特征；CPTD-Ⅱ表现为C16异常增高同时C2显著减低；MAD缺陷的特点是从C4到C12大范围的异常增高；MTPD则表现C12和C16的同时增高；CACTD类似于CPTD-Ⅱ呈现C16增高而C2降低,但异常的幅度较CPTD-Ⅱ小.此外,计算比较各酰基肉碱与乙酰肉碱的比值(Cn/C2)在不同病症亦呈现出特异性结果.结论 应用成纤维细胞体外特定条件培养结合串联质谱酰基肉碱谱分析,可诊断和鉴别诊断各种遗传性线粒体脂肪酸β-氧化代谢障碍病,是一个较为简便特异的方法.%Objective To establish diagnostic method on mitochondrial fatty acid (3 - oxidation disorders (FAODs) using in -vitro probe assay based on MS/MS. Methods Human fibroblasts from normal controls (re =6) and patients with FAODs (re = 14) were used, which including SCAD (n = 1), MCAD (re =3), VL-CAD (re =3), CPT-II (re =2), MTP (re =2), MCD (re =2) and CACT (re = 1). The cells were cultured in medium loaded with unlabelled palmitic acid for 96 h at 37℃. The acylcarnitine profiles in the medium was analyzed by tandem MS. The clinical differential diagnosis was made based on the quantitative acylcarinitine and its ratios. Results Compared with normal control, C2 decreased significantly in all kinds of patients and the other aclycarnitines displayed in different styles in varied diseases. C4, C8, C12 and C16 elevated significantly in SCADD, MCADD, VLCADD and CPTD -II respectively; the feature of MADD is seen with extensive abnormal increase from C4 to C12; MTPD displayed increase of C12 and C16 in concurrent; while similar to CPTD -II, CACTD showed the increase of C16, but decrease of C2, just with less obvious abnormality. Besides, it is observed that the ratios (Cn/C2) of acylcarnitine (Cn) and acetylcarnitine (C2) showed specific results in varied diseases. Conclusion It is a practical and effective approach to diagnose and distinguish various inherited mitochondrial fatty acid (3 - oxidation disorders using in - vitro probe assay combined with tandem MS analysis. The prospect of this method has good value in clinical application.
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