Gas chromatographic–mass spectrometric urinary metabolome analysis to study mutations of inborn errors of metabolism

Abstract

Urine contains numerous metabolites, and can provide evidence for the screening or molecular diagnosis of many inborn errors of metabolism (IEMs). The metabolomic analysis of urine by the combined use of urease pretreatment, stable-isotope dilution, and capillary gas chromatography/mass spectrometry offers reliable and quantitative data for the simultaneous screening or molecular diagnosis of more than 130 IEMs. Those IEMs include hyperammonemias and lactic acidemias, and the IEMs of amino acids, pyrimidines, purines, carbohydrates, and others including primary hyperoxalurias, hereditary fructose intolerance, propionic acidemia, and methylmalonic acidemia. Metabolite analysis is comprehensive for mutant genotypes. Enzyme dysfunction-either by the abnormal structure of an enzyme/apoenzyme, the reduced quantity of a normal enzyme/apoenzyme, or the lack of a coenzyme-is involved. Enzyme dysfunction-either by an abnormal regulatory gene, abnormal sub-cellular localization, or by abnormal post-transcriptional or post-translational modification-is included. Mutations-either known or unknown, common or uncommon-are involved. If the urine metabolome approach can accurately observe quantitative abnormality for hundreds of metabolites, reflecting 100 different disease-causing reactions in a body, then it is possible to simultaneously detect different mutant genotypes of far more than tens of thousands.

Metabolomics Study of Stepwise Hepatocarcinogenesis From the Model Rats to Patients: Potential Biomarkers Effective for Small Hepatocellular Carcinoma Diagnosis

“…Within the framework of systems biology, metabolomics focuses on the quantitative measurement of holistic endogenous metabolites and is increasingly used in clinical fields that focus on the pathophysiological and diagnostic study of diseases (6). Metabolic fingerprinting and metabolite biomarkers have been studied for use in the discrimination or diagnosis of carcinoma (7,8), diabetes mellitus (9) and inborn errors (10). Nontarget metabolomics approaches have also been used to search for new biomarkers and to explore the mechanism of carcinogenesis in hepatic diseases (11)(12)(13)(14)(15)(16)(17)(18)(19)(20).…”

Hyphenated Techniques in Gas Chromatography

“…Years later, improved GC-MS instruments were commercialized with the development of computer-controlled quadrupole mass spectrometer for fast acquisition to accommodate the separation in gas chromatograph. Since then, its applications in various areas of sciences has made it a routine method of choice for (bio)organic analysis (Kuhara, 2005).…”

Future of Liquid Chromatography–Mass Spectrometry in Metabolic Profiling and Metabolomic Studies for Biomarker Discovery

“…Metabolomics has its origins in the early orthomolecular medicine work pioneered by Robinson and Pauling [5][6][7][8][9][10], as well as in the metabolic flux and metabolic control analysis work of Kacser [11][12][13][14][15][16] (additionally, the influence of metabolic profiling in the diagnosis and screening for inborn errors of metabolism [17][18][19] cannot be ignored, but will not be discussed here). Pauling defined orthomolecular medicine as both the preservation of optimum health and the treatment of disease through variation of the concentrations of endogenous substances required for health [5].…”

“…Metabolite quantitation in traditional chromatography-MS-based targeted analyses has relied on the use of stable-isotope dilution to effectively minimize the uncertainty in the measurement (reviewed in [19,[135][136][137]). In this approach, stable-isotope-labeled analogues (typically labeled with 2 H, 13 C, or 15 N) of the target analyte(s) are spiked into the sample prior to treatment, in order to account for both systematic errors due to the sample processing approach and systematic errors encountered during sample analysis by GC-or LC-MS.…”