PLASMA ACYLCARNITINE AND URINARY ORGANIC ACID PROFILING FOR THE DIAGNOSIS OF FATTY ACID OXIDATION DISORDER AND ORGANIC ACIDURIAS USING TANDEM MASS SPECTROMETRY (MS/MS) AND GAS CHROMATOGRAPHY TANDEM WITH MASS SPECTROMETRY (GC-MS): A RETROSPECTIVE STUDY

Introduction: Plasma acylcarnitines (PLAC) and urine organic acids (UOA) are key diagnostic markers for some Inborn Errors of Metabolism (IEM) such as fatty acid oxidation disorders (FAODs) and disorders related to organic acid metabolism.

Objective: This study aims to determine the PLAC and UOA profiles of Filipino newborn infants at risk of IEM using FIA-MS/MS and GC-MS. Furthermore, this study describes the process of identifying true positive cases of FAODs and some organic acidurias.

Methodology: PLAC and UOA analyses were performed using Waters® MS/MS and Agilent® GC-MS. Results were obtained from databases and IEM records of the Biochemical Genetics Laboratory from 2015 to 2021. Descriptive statistics were used to evaluate the detection rates of FAODs and Organic Acidurias.

Results: Data from 2015-2021 showed that 176 out of 1642 infants screened at risk for FAODs and organic acidurias were true positive. The use of MS/MS and GC-MS yielded a detection rate of 10.6% in 104 Filipino newborn infants with FAOD, compared to 72 infants with organic acidurias. Medium-chain acyl-CoA dehydrogenase deficiency was reported to be the most common FAOD with 67 cases. Organic acidurias such as glutaric aciduria types 1 and 3-

Conclusion: This article presents PLAC and UOA profiles of Filipino newborn infants with FAOD and organic aciduria. This study highlights the importance of conducting confirmatory tests to identify true positive cases. Therefore, this study warrants further work on validating analytical methodologies for targeted measurements of IEMs biomarkers. Methylcrotonyl-CoA carboxylase deficiency was found to be prevalent in 34 and 26 cases, respectively.