title: Quantitative acylcarnitine determination by UHPLC-MS/MS--Going beyond tandem MS acylcarnitine "profiles".
abstract: Tandem MS "profiling" of acylcarnitines and amino acids was conceived as a first-tier screening method, and its application to expanded newborn screening has been enormously successful. However, unlike amino acid screening (which uses amino acid analysis as its second-tier validation of screening results), acylcarnitine "profiling" also assumed the role of second-tier validation, due to the lack of a generally accepted second-tier acylcarnitine determination method. In this report, we present results from the application of our validated UHPLC-MS/MS second-tier method for the quantification of total carnitine, free carnitine, butyrobetaine, and acylcarnitines to patient samples with known diagnoses: malonic acidemia, short-chain acyl-CoA dehydrogenase deficiency (SCADD) or isobutyryl-CoA dehydrogenase deficiency (IBD), 3-methyl-crotonyl carboxylase deficiency (3-MCC) or ß-ketothiolase deficiency (BKT), and methylmalonic acidemia (MMA). We demonstrate the assay's ability to separate constitutional isomers and diastereomeric acylcarnitines and generate values with a high level of accuracy and precision. These capabilities are unavailable when using tandem MS "profiles". We also show examples of research interest, where separation of acylcarnitine species and accurate and precise acylcarnitine quantification is necessary.
authors.affiliation: Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Minkler
authors.affiliation: Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
authors.forename: Maria S K
authors.initials: MS
authors.lastname: Stoll
authors.affiliation: Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Ingalls
authors.affiliation: Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
authors.forename: Janos
authors.initials: J
authors.lastname: Kerner
authors.affiliation: Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA. Electronic address: charles.hoppel@case.edu.
authors.forename: Charles L
authors.initials: CL
authors.lastname: Hoppel
mesh_terms: D000102:Acetyl-CoA C-Acyltransferase / Q000097:blood / Q000134:cerebrospinal fluid / Q000172:deficiency* / Q000652:urine; D042964:Acyl-CoA Dehydrogenase / Q000097:blood / Q000134:cerebrospinal fluid / Q000172:deficiency* / Q000652:urine; D000592:Amino Acid Metabolism, Inborn Errors / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000652:urine; D001622:Betaine / Q000031:analogs & derivatives / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D019735:Carbon-Carbon Ligases / Q000097:blood / Q000134:cerebrospinal fluid / Q000172:deficiency* / Q000652:urine; D002331:Carnitine / Q000031:analogs & derivatives* / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000592:standards; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007536:Isomerism; D008052:Lipid Metabolism, Inborn Errors / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000652:urine; D008297:Male; D015997:Neonatal Screening; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000592:standards; D056806:Urea Cycle Disorders, Inborn / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000652:urine
chemical_list: C116917:acylcarnitine; D001622:Betaine; C002889:gamma-butyrobetaine; D042964:Acyl-CoA Dehydrogenase; D000102:Acetyl-CoA C-Acyltransferase; D019735:Carbon-Carbon Ligases; D002331:Carnitine
keywords: Carnitine analysis; Metabolism research; Newborn screening follow-up; Quantitative acylcarnitine analysis; Second-tier analysis