中文摘要：

背景：Methylmalonic 酸尿(MMA ) 是在中国的器官的酸尿的最经常的疾病。各种各样的生物化学的策略为 MMA 的出生前的诊断被跟随。然而，后来， MMA 影响的胎儿减少了 methylmalonic 酸的排泄，出生前的生物化学的诊断的困难是明显的。煤气的层析团分光术(GC/MS ) 和双人脚踏车团分光术(ESI/MS/MS ) 允许我们在影响胎儿识别疾病。这研究的目的是在 MMA 的出生前的诊断在羊膜的液体决定有机酸和全部的人半胱氨酸的分析的价值。方法：临床诊断并且有 MMA 的九个职业人员乐队的结果并且出生前在风险基于九个胎儿的生物化学的分析诊断因为 MMA 被调查。从在为 MMA 的风险的怀孕和新陈代谢的联盟者正常怀孕的羊膜的液体样品在 16 点被获得 - 24 星期怀孕期。Methylmalonic 酸和甲基枸橼酸被 GC/MS 测量， propionylcarnitine 被 ESI/MS/MS 分析，并且全部的人半胱氨酸由荧光极化免疫分析是坚定的。结果：在二怀孕， methylmalonic 酸的高水平，甲基枸橼酸， propionylcarnitine，和总数，人半胱氨酸在胎儿显示了联合 MMA 和 homocysteinemia。继续的怀孕和收到的维生素 B12 作为出生前的处理，和其它补充的母亲之一终止了她的怀孕。在一个，怀孕， methylmalonic 酸的显著地提高的层次，甲基枸橼酸，和 propionylcarnitine，和正常全部的人半胱氨酸铺平被发现在胎儿显示孤立的 MMA；流产在这个案例上被执行。在另外的六怀孕，上述提及的代谢物的所有层次是正常的建议胎儿没被 MMA 影响。diagnoses 被严峻的尿有机酸和血浆总数人半胱氨酸在交货以后证实。结论：MMA 的新陈代谢的畸形在怀孕期早发生。在羊膜的液体的全部的人半胱氨酸的水平可以是胎儿的联合 MMA 和 homocysteinemia 的另外的指示物。在羊膜的液体的全部的人半胱氨酸水平的决心可以为疾病的出生前的诊断成为一个方便?

英文摘要：

Background Methylmalonic aciduria （MMA） is the most frequent disease of organic aciduria in China. Various biochemical strategies are followed for the prenatal diagnosis of MMA. However, since fetuses affected by MMA have decreased excretion of methylmalonic acid, the difficulties of prenatal biochemical diagnosis are obvious. Gas chromatography mass spectrometry （GC/MS） and tandem mass spectrometry （ESl/MS/MS） have allowed us to identify the disease in affected fetuses. The aim of this study was to determine the value of analysis of organic acids and total homocysteine in amniotic fluid in prenatal diagnosis of MMA. Methods The clinical diagnoses and outcomes of nine probands with MMA and the prenatal diagnoses based on biochemical analysis of nine fetuses at risk for MMA were investigated. Amniotic fluid samples from pregnancies at risk for MMA and metabolically normal pregnancies were obtained at 16-24 weeks of gestation. Methylmalonic acid and methylcitric acid were measured by GC/MS, propionylcarnitine was analyzed by ESl/MS/MS, and total homocysteine was determined by fluorescence polarization immunoassay. Results In two pregnancies, high levels of methylmalonic acid, methylcitric acid, propionylcarnitine, and total homocysteine indicated combined MMA and homocysteinemia in the fetuses. One of the mothers continued pregnancy and received cobalamin supplement as prenatal treatment, and the other terminated her pregnancy. In one pregnancy, significantly elevated levels of methylmalonic acid, methylcitric acid, and propionylcarnitine, and normal level of total homocysteine was found indicating isolated MMA in the fetus; abortion was performed on this case. In the other six pregnancies, all the levels of the above mentioned metabolites were normal suggesting that the fetuses were not affected by MMA. The diagnoses were confirmed after delivery by testing urinary organic acids and plasma total homocysteine. Conclusions The metabolic abnormalities of MMA occur early in gestation. The level of to