Rapid and sensitive method for prenatal diagnosis of propionic acidemia using stable isotope dilution gas chromatography-mass spectrometry and urease pretreatment.
Propionic acidemia is one of the most frequent inborn errors of metabolism caused by a deficiency of propionyl-CoA carboxylase. Methylcitric acid, a key indicator of this disorder, is increased in amniotic fluid when a fetus is affected. Therefore, the direct chemical analysis of cell-free amniotic fluid for methylcitric acid, using stable isotope dilution gas chromatography-mass spectrometry, was carried out for the prenatal diagnosis of propionic acidemia. We developed a simple, highly sensitive, and accurate method for quantitation of this polar methylcitric acid in amniotic fluids by applying a simplified urease pretreatment which we devised earlier for urine. As the recovery of methylcitric acid from amniotic fluid was as high as 91% with a coefficient of variation lower than 3% in this procedure, only 0.02 ml of sample was required for the analysis of the affected fetus. This new procedure takes 1 h for sample pretreatment, including derivatization, and 15 min for GC-MS measurement and provides final results within 1.5 h.
Inoue
Y
Y
Division of Human Genetics, Medical Research Institute, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa 9200293, Japan. yosh@kanazawa-med.ac.jp
Kuhara
T
T
D000653:Amniotic Fluid / Q000378:metabolism; D019343:Citric Acid / Q000378:metabolism; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D007554:Isotopes; D008661:Metabolism, Inborn Errors / Q000175:diagnosis*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D011422:Propionates / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014510:Urease / Q000378:metabolism*
D007554:Isotopes; D011422:Propionates; D019343:Citric Acid; D014510:Urease; C029658:propionic acid