Development of Second-Tier Liquid Chromatography-Tandem Mass Spectrometry Analysis for Expanded Newborn Screening in Japan

Abstract

To minimize false-positive cases in newborn screening by tandem mass spectrometry in Japan, practical second-tier liquid chromatography-tandem mass spectrometry analyses have been developed using a multimode ODS column with a single set of mobile phases and different gradient elution programs specific to the analysis of acylcarnitines, acylglycines, amino acids, and organic acids. Most analyses were performed using underivatized samples, except for analysis of methylcitric acid, and careful conditioning of the column was necessary for analyses of organic acids. Our second-tier tests enabled us to measure many metabolites useful for detection of target disorders, including allo-isoleucine, homocysteine, methylmalonic acid, and methylcitric acid. We found that accumulation of 3-hydroxyglutaric acid was specific to glutaric acidemia type I and that the ratio of 3-hydroxyisovaleric acid to 3-hydroxyisovalerylcarnitine was useful to detect newborns of mothers with 3-methylcrotonyl-CoA carboxylase deficiency. Data from the analysis of short-chain acylcarnitine and acylglycine were useful for differential diagnosis in cases positive for C5-OH-acylcarnitine or C5-acylcarnitine.

Application of the Artificial Intelligence Algorithm Model for Screening of Inborn Errors of Metabolism

“…Thus, there is an urgent clinical need to improve the neonatal screening efficiency of IEMs, researchers are making efforts to this end, and some gratifying research results have been achieved. Yosuke developed a second-tier liquid chromatography- (LC-) MS/MS analysis method to minimize false-positive cases in newborn screening by MS/MS ( 15 ). Their works could effectively decrease the false-positive rate of glutaric acidemia type I (GA-I), 3-methylcrotonyl-CoA carboxylase deficiency (3-MCCD), and were useful for differential diagnosis in cases positive for C5-OHacylcarnitine or C5-acylcarnitine.…”

Quantitation of non-derivatized free amino acids for detecting inborn errors of metabolism by incorporating mixed-mode chromatography with tandem mass spectrometry

“…Most reported LC-MS/MS methods for amino acids have not reported on the separation of Leu, Ile, and allo-Ile, which could be due to analytical limitations or differing clinical needs. While there are reported LC-MS/MS methods with the ability to chromatographically resolve these three isomers, they tend to be narrowly focused on a small numbers of amino acids [17] , [18] , [25] , [26] . However, given the need for a comprehensive amino acid panel, it was more appropriate to develop a complete assay that could provide an inclusive panel while simultaneously resolving critical structural and stereoisomers in a short period of time.…”

“…Recently, mixed-mode (MM) chromatography has been reported as an alternative strategy for amino acid analysis [15] , [16] , [17] , [18] , [19] , [20] . However, most MM amino acid methods published to date either do not effectively separate the leucine isomers or have smaller panel sizes.…”

Incorporation of second‐tier tests and secondary biomarkers to improve positive predictive value (PPV) rate in newborn metabolic screening program

“…Thus, it is essential to provide a separate testing protocol for second‐tier tests 7 . These tests are available for some neonatal screening programs of IEMs, such as tyrosinemia type I, propionic acidemia, maple syrup urine disease (MSUD), congenital adrenal hyperplasia (CAH), hyperammonemia‐hyperornithinemia‐hyperhomocitrullinemia (HHH) syndrome, galactosemia, and lysosomal storage diseases 8–11 …”

“…7 These tests are available for some neonatal screening programs of IEMs, such as tyrosinemia type I, propionic acidemia, maple syrup urine disease (MSUD), congenital adrenal hyperplasia (CAH), hyperammonemiahyperornithinemia-hyperhomocitrullinemia (HHH) syndrome, galactosemia, and lysosomal storage diseases. [8][9][10][11] This study is a retrospective investigation conducted on 39987 Iranian newborns referring to Nilou medical laboratory for the purpose of neonatal screening for IEMs. These babies were from 20 different provinces across Iran.…”