Diagnosis and therapeutic monitoring of inborn errors of creatine metabolism and transport using liquid chromatography-tandem mass spectrometry in urine, plasma and CSF.
Biochemical detection of inborn errors of creatine metabolism or transport relies on the analysis of three main metabolites in biological fluids: guanidinoacetate (GAA), creatine (CT) and creatinine (CTN). Unspecific clinical presentation of the diseases might be the cause that only few patients have been diagnosed so far. We describe a LC-MS/MS method allowing fast and reliable diagnosis by simultaneous quantification of GAA, CT and CTN in urine, plasma and cerebrospinal fluid (CSF) and established reference values for each material. For quantification deuterated stable isotopes of each analyte were used as internal standards. GAA, CT and CTN were separated by reversed-phase HPLC. The characterization was carried out by scanning the ions of each compound by negative ion tandem mass spectrometry. Butylation is needed to achieve sufficient signal intensity for GAA and CT but it is not useful for analyzing CTN. The assay is linear in a broad range of analyte concentrations usually found in urine, plasma and CSF. Comparison of the "traditional" cation-exchange chromatography and LC-MS/MS showed proportional differences but linear relationships between the two methods. The described method is characterized by high speed and linearity over large concentration ranges comparable to other published LC-MS methods but with higher sensitivity for GAA and CT. In addition, we present the largest reference group ever published for guanidino compounds in all relevant body fluids. Therefore this method is applicable for high-throughput approaches for diagnosis and follow-up of inborn errors of creatine metabolism and transport.
Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Germany.
Dorothea
D
Haas
Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Germany.
Hongying
H
Gan-Schreier
Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Germany.
Claus-Dieter
CD
Langhans
Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Germany.
Alexandros
A
Anninos
Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Germany.
Gisela
G
Haege
Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Germany.
Peter
P
Burgard
Department of Paediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Andreas
A
Schulze
Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Germany.
Georg F
GF
Hoffmann
Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Germany. Electronic address: juergen.okun@med.uni-heidelberg.de.
Jürgen G
JG
Okun
D016022:Case-Control Studies; D002648:Child; D003401:Creatine / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine*; D003404:Creatinine / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods* / Q000592:standards; D030342:Genetic Diseases, Inborn / Q000175:diagnosis*; D005998:Glycine / Q000031:analogs & derivatives* / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D006801:Humans; D007223:Infant; D008297:Male; D012015:Reference Standards; D055815:Young Adult
D003404:Creatinine; C004946:glycocyamine; D003401:Creatine; D005998:Glycine
Cerebrospinal fluid; Creatine; Creatine deficiency syndromes; Creatinine; Guanidinoacetate; Liquid chromatography–tandem mass spectrometry; Plasma; Urine