• MeSH
• chromatografie na tenké vrstvě MeSH
• fibroblasty enzymologie   MeSH
• leucin MeSH
• lidé MeSH
• lyasy oxokyselin nedostatek   metabolismus   MeSH
• předškolní dítě MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• 3-hydroxy-3-methylglutaryl-coenzyme A lyase MeSH Prohlížeč
• leucin MeSH
• lyasy oxokyselin MeSH

3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (HMGCLD) is a rare inborn error of ketone body synthesis and leucine degradation, caused by mutations in the HMGCL gene. In order to obtain a comprehensive view on this disease, we have collected clinical and biochemical data as well as information on HMGCL mutations of 37 patients (35 families) from metabolic centers in Belgium, Germany, The Netherlands, Switzerland, and Turkey. All patients were symptomatic at some stage with 94% presenting with an acute metabolic decompensation. In 50% of the patients, the disorder manifested neonatally, mostly within the first days of life. Only 8% of patients presented after one year of age. Six patients died prior to data collection. Long-term neurological complications were common. Half of the patients had a normal cognitive development while the remainder showed psychomotor deficits. We identified seven novel HMGCL mutations. In agreement with previous reports, no clear genotype-phenotype correlation could be found. This is the largest cohort of HMGCLD patients reported so far, demonstrating that HMGCLD is a potentially life-threatening disease with variable clinical outcome. Our findings suggest that the clinical course of HMGCLD cannot be predicted accurately from HMGCL genotype. The overall outcome in HMGCLD appears limited, thus rendering early diagnosis and strict avoidance of metabolic crises important.

• Klíčová slova
• Enzyme activity, Fatty acid metabolism, Ketogenesis, Ketone body synthesis, Leucine degradation, Organic aciduria,
• MeSH
• acetyl-CoA-C-acetyltransferasa nedostatek   MeSH
• dítě MeSH
• dospělí MeSH
• genetické asociační studie MeSH
• hodnocení výsledků pacienta MeSH
• ketolátky metabolismus   MeSH
• kojenec MeSH
• leucin metabolismus   MeSH
• lidé MeSH
• lyasy oxokyselin genetika   MeSH
• mastné kyseliny metabolismus   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace MeSH
• předškolní dítě MeSH
• vrozené poruchy metabolismu aminokyselin * komplikace   diagnóza   dietoterapie   patofyziologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• Geografické názvy
• Belgie MeSH
• Německo MeSH
• Nizozemsko MeSH
• Švýcarsko MeSH
• Turecko MeSH
• Názvy látek
• 3-hydroxy-3-methylglutaryl-coenzyme A lyase MeSH Prohlížeč
• acetyl-CoA-C-acetyltransferasa MeSH
• ketolátky MeSH
• leucin MeSH
• lyasy oxokyselin MeSH
• mastné kyseliny MeSH

3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (HMGCLD) is a rare autosomal recessively inherited metabolic disorder. Patients suffer from avoidable neurologically devastating metabolic decompensations and thus would benefit from newborn screening (NBS). The diagnosis is currently made by measuring dry blood spot acylcarnitines (C5OH and C6DC) followed by urinary organic acid profiling for the differential diagnosis from several other disorders. Using untargeted metabolomics (reversed-phase UHPLC coupled to an Orbitrap Elite hybrid mass spectrometer) of plasma samples from 5 HMGCLD patients and 19 age-matched controls, we found 3-methylglutaconic acid and 3-hydroxy-3-methylglutaric acid, together with 3-hydroxyisovalerylcarnitine as the most discriminating metabolites between the groups. In order to evaluate the NBS potential of these metabolites we quantified the most discriminating metabolites from untargeted metabolomics in 23 blood spots from 4 HMGCLD patients and 55 controls by UHPLC tandem mass spectrometry. The results provide a tool for expanded NBS of HMGCLD using tandem mass spectrometry. Selected reaction monitoring transition 262/85 could be used in a first-tier NBS analysis to screen for elevated 3-hydroxyisovalerylcarnitine. In a positive case, a second-tier analysis of 3-hydroxy-3-methylglutaric acid and 3-methylglutaconic acid in a dry blood spot using UHPLC tandem mass spectrometry instruments confirms the diagnosis. In conclusion, we describe the identification of new diagnostic biomarkers for HMGCLD and their application in NBS in dry blood spots. By using second-tier testing, all patients with HMGCLD were unequivocally and correctly diagnosed.

• Klíčová slova
• 3‐hydroxy‐3‐methylglutaryl‐coenzyme A lyase deficiency, HMG‐CoA lyase, acylcarnitines, biomarkers, metabolomics, newborn screening, organic acids,
• Publikační typ
• časopisecké články MeSH

Specific diagnostic markers are the key to effective diagnosis and treatment of inborn errors of metabolism (IEM). Untargeted metabolomics allows for the identification of potential novel diagnostic biomarkers. Current separation techniques coupled to high-resolution mass spectrometry provide a powerful tool for structural elucidation of unknown compounds in complex biological matrices. This is a proof-of-concept study testing this methodology to determine the molecular structure of as yet uncharacterized m/z signals that were significantly increased in plasma samples from patients with phenylketonuria and 3-hydroxy-3-methylglutaryl-CoA lyase deficiency. A hybrid linear ion trap-orbitrap high resolution mass spectrometer, capable of multistage fragmentation, was used to acquire accurate masses and product ion spectra of the uncharacterized m/z signals. In order to determine the molecular structures, spectral databases were searched and fragmentation prediction software was used. This approach enabled structural elucidation of novel compounds potentially useful as biomarkers in diagnostics and follow-up of IEM patients. Two new conjugates, glutamyl-glutamyl-phenylalanine and phenylalanine-hexose, were identified in plasma of phenylketonuria patients. These novel markers showed high inter-patient variation and did not correlate to phenylalanine levels, illustrating their potential added value for follow-up. As novel biomarkers for 3-hydroxy-3-methylglutaryl-CoA lyase deficiency, three positional isomers of 3-methylglutaconyl carnitine could be detected in patient plasma. Our results highlight the applicability of current accurate mass multistage fragmentation techniques for structural elucidation of unknown metabolites in human biofluids, offering an unprecedented opportunity to gain further biochemical insights in known inborn errors of metabolism by enabling high confidence identification of novel biomarkers.

• Klíčová slova
• 3-hydroxy-3-methylglutaryl coenzyme a lyase deficiency, Biomarkers, Metabolomics, Next generation metabolic screening, Phenylketonuria, Structural elucidation,
• MeSH
• acetyl-CoA-C-acetyltransferasa krev   nedostatek   MeSH
• biologické markery analýza   krev   chemie   MeSH
• chemická frakcionace metody   MeSH
• chromatografie kapalinová MeSH
• fenylketonurie krev   diagnóza   MeSH
• lidé MeSH
• metabolické nemoci krev   diagnóza   MeSH
• metabolom MeSH
• metabolomika metody   MeSH
• molekulární konformace MeSH
• reprodukovatelnost výsledků MeSH
• software MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• vrozené poruchy metabolismu aminokyselin krev   diagnóza   MeSH
• vrozené poruchy metabolismu krev   diagnóza   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetyl-CoA-C-acetyltransferasa MeSH
• biologické markery MeSH

Clinical metabolomics aims at finding statistically significant differences in metabolic statuses of patient and control groups with the intention of understanding pathobiochemical processes and identification of clinically useful biomarkers of particular diseases. After the raw measurements are integrated and pre-processed as intensities of chromatographic peaks, the differences between controls and patients are evaluated by both univariate and multivariate statistical methods. The traditional univariate approach relies on t-tests (or their nonparametric alternatives) and the results from multiple testing are misleadingly compared merely by p-values using the so-called volcano plot. This paper proposes a Bayesian counterpart to the widespread univariate analysis, taking into account the compositional character of a metabolome. Since each metabolome is a collection of some small-molecule metabolites in a biological material, the relative structure of metabolomic data, which is inherently contained in ratios between metabolites, is of the main interest. Therefore, a proper choice of logratio coordinates is an essential step for any statistical analysis of such data. In addition, a concept of b-values is introduced together with a Bayesian version of the volcano plot incorporating distance levels of the posterior highest density intervals from zero. The theoretical background of the contribution is illustrated using two data sets containing samples of patients suffering from 3-hydroxy-3-methylglutaryl-CoA lyase deficiency and medium-chain acyl-CoA dehydrogenase deficiency. To evaluate the stability of the proposed method as well as the benefits of the compositional approach, two simulations designed to mimic a loss of samples and a systematical measurement error, respectively, are added.

• Klíčová slova
• Bayesian inference, Compositional data, High-dimensional data, Multiple hypotheses testing, Untargeted metabolomics, Volcano plot,
• MeSH
• acetyl-CoA-C-acetyltransferasa nedostatek   metabolismus   MeSH
• acyl-CoA-dehydrogenasa nedostatek   metabolismus   MeSH
• Bayesova věta * MeSH
• datové soubory jako téma MeSH
• lidé MeSH
• metabolomika * MeSH
• vrozené poruchy metabolismu aminokyselin metabolismus   MeSH
• vrozené poruchy metabolismu tuků metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetyl-CoA-C-acetyltransferasa MeSH
• acyl-CoA-dehydrogenasa MeSH