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Reliable prenatal diagnosis of Canavan disease by measuring N ‐acetylaspartate in amniotic fluid using liquid chromatography tandem mass spectrometry
Author(s) -
AlDirbashi Osama Y.,
Kurdi Wesam,
Imtiaz Faiqa,
Ahmad Asmahan M.,
AlSayed Moeenaldeen,
Tulbah Maha,
AlNemer Maha,
Rashed Mohamed S.
Publication year - 2009
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.2223
Subject(s) - amniotic fluid , derivatization , chemistry , chromatography , tandem mass spectrometry , mass spectrometry , fetus , pregnancy , genetics , biology
Objective Prenatal diagnosis of Canavan disease by measuring N ‐acetylaspartic acid (NAA) in amniotic fluid is reliable and preferred over aspartoacylase enzyme assay especially in populations with unknown mutations. Typically based on GC–MS, existing methods are time‐consuming and laborious. We developed a novel LC–MS/MS method for determination of NAA in amniotic fluid with minimal sample preparation. Method NAA and d 3 ‐NAA were detected by negative‐ion electrospray ionization‐MS/MS. Quantification was achieved by standard addition using six 0.1 mL portions of each specimen enriched with increasing NAA amounts (0, 0.05, 0.1, 0.2, 0.3, and 0.4 µg) and endogenous NAA was calculated by extrapolation. Results Injection‐to‐injection time was 2 min whereas the turn around time from sample receipt was about 1 h. Intraday ( n = 10) and interday ( n = 10) variations were less than 9.4%. The reference range determined using gestation‐matched controls ( n = 12) of 1.1–2.7 µmol/L is in agreement with the literature. Specimens from at‐risk pregnancies with established diagnosis ( n = 4) were successfully analyzed. Conclusion We developed a new method that enables reliable, sensitive, and selective determination of NAA in a small volume of amniotic fluid for the prenatal diagnosis of Canavan disease. The simple sample preparation adopted in this work precluded the necessity for extraction and derivatization. Copyright © 2009 John Wiley & Sons, Ltd.