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.

• 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

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.

• 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