Background. Patients with inborn errors of metabolism (IEM) pose specific management challenges, ... more Background. Patients with inborn errors of metabolism (IEM) pose specific management challenges, considering their multisystem involvement. Among them, children and adults with organic acidemias (OA) and other disorders of the amino acid metabolism have a high risk for severe metabolic events that need to be recognized and promptly treated, and therefore require frequent clinical and biochemical evaluations. The novel highly pathogenic SARS-CoV2 virus appeared in Europe in the first trimester of 2020. This pandemic has a huge impact on the health care systems all over the world, interrupting the follow-up of many chronic diseases. For metabolic patients, travel to reference units may be reduced due to mobility restrictions but more importantly, attendance to medical facilities can be a risk of infection that can be a danger in itself but also trigger a metabolic decompensation.Methods. During the first coronavirus disease (COVID-19) outbreak in Spain from March to June 2020, we desi...
Mitochondrial fatty acid β-oxidation (FAO) contributes a large proportion to the body’s energy ne... more Mitochondrial fatty acid β-oxidation (FAO) contributes a large proportion to the body’s energy needs in fasting and in situations of metabolic stress. Most tissues use energy from fatty acids, particularly the heart, skeletal muscle and the liver. In the brain, ketone bodies formed from FAO in the liver are used as the main source of energy. The mitochondrial fatty acid oxidation disorders (FAODs), which include the carnitine system defects, constitute a group of diseases with several types and subtypes and with variable clinical spectrum and prognosis, from paucisymptomatic cases to more severe affectations, with a 5% rate of sudden death in childhood, and with fasting hypoketotic hypoglycemia frequently occurring. The implementation of newborn screening programs has resulted in new challenges in diagnosis, with the detection of new phenotypes as well as carriers and false positive cases. In this article, a review of the biochemical markers used for the diagnosis of FAODs is presen...
En el area de la tecnologia de los alimentos, las novedosas tecnicas de extraccion que se basan e... more En el area de la tecnologia de los alimentos, las novedosas tecnicas de extraccion que se basan en el empleo de dioxido de carbono supercritico poseen claras ventajas sobre aquellas consideradas convencionales. Con el fin de contribuir al avance sobre la aplicacion de esta tecnica junto con el desarrollo de nuevos productos de mayor calidad y el aprovechamiento de subproductos se planteo: la disminucion del contenido en colesterol de la grasa de la nata mediante la extraccion con CO2 supercritico, siendo las condiciones de 14,5 mpa a 40, 50 y 60 grados c las que producian el maximo rendimiento de extraccion (75%). Otro objetivo fue el fraccionamiento de la grasa lactea de la nata por el mismo metodo, observandose que era imprescindible el uso de soportes solidos (bolas de vidrio) para favorecer la maxima extraccion de los trigliceridos. Previamente se estimo la composicion de la grasa lactea identificandose 181 especies, algunas de ellas por primera vez. Asi mismo, se procedio al es...
Incidental findings on newborn screening (NBS) are results that are not the target of screening w... more Incidental findings on newborn screening (NBS) are results that are not the target of screening within a given NBS program, but rather are found as a result of the screening and resulting diagnostic workup for that target. These findings may not have an immediate clinical impact on the newborn, but are sometimes an additional benefit of NBS programs and may be considered secondary targets of NBS programs. This work describes four case reports that had incidental findings on the NBS, which eventually led to the diagnosis of another metabolic disease instead of the one that was initially suspected. The first case was a new defect in the cationic amino acid transporter-2 (CAT-2), which was oriented as an arginase-1 deficiency in the newborn. The second case was a maternal glutaric aciduria type 1 (GA-1) that mimicked a carnitine transporter deficiency in the newborn. The third report was a case of lysinuric protein intolerance (LPI), which appeared as high levels of citrulline on the N...
This review discusses the development of capillary electrophoresis with laser-induced detection a... more This review discusses the development of capillary electrophoresis with laser-induced detection and mass spectrometry techniques for the analysis of urinary oligosaccharides to screen for human oligosaccharidoses and related disorders. Capillary electrophoresis is suitable for the analysis of urinary oligosaccharides. It has a high resolution efficiency, and when it is coupled to a laser-induced fluorescence detector system, it offers an optimal analytical sensitivity. Mass spectrometry techniques have evolved as powerful tools for glycan analyses, are important tools for the analysis of oligosaccharide structures, and offer precise results, analytical versatility, very high sensitivity, high precision and high speed. Mass spectrometry is tolerant of mixtures and is a natural choice for the analysis of this class of molecules. The urine oligosaccharide profiles from healthy controls and patients diagnosed with different lysosomal storage diseases (fucosidosis, α-mannosidosis, GM1 ga...
Succinic semialdehyde dehydrogenase deficiency (gamma-hydroxybutyric aciduria) is a rare neuromet... more Succinic semialdehyde dehydrogenase deficiency (gamma-hydroxybutyric aciduria) is a rare neurometabolic disease caused by a deficiency in gamma-aminobutyric degradation, resulting in an increase in gamma-hydroxybutyric acid in biological fluids. The clinical spectrum is heterogeneous, including a variety of neurological manifestations and psychiatric symptoms. The treatment usually used is vigabatrin, but its clinical efficacy is under discussion. We present two affected siblings. The older brother was examined when he was 2.5 years old due to psychomotor and developmental delay, disturbances in motor coordination, axial hypotonia and language disability. His younger brother had mild axial hypotonia when 5 months old. Metabolic studies demonstrated a high plasma and urine concentration of gamma-hydroxybutyric acid. Mutation analysis of the gene ALDH5A1 confirmed the disease. After 1 year of treatment with low-doses of vigabatrin of the older patient, a decrease in gamma-hydroxybutyr...
Clinica chimica acta; international journal of clinical chemistry, 2015
Cystathionine β-synthase (CBS) is released into plasma from organs expressing this enzyme. Decrea... more Cystathionine β-synthase (CBS) is released into plasma from organs expressing this enzyme. Decreased plasma CBS activity has been demonstrated in CBS-deficient patients with 16 different genotypes. The aim of this study was to determine plasma CBS activity in patients carrying 11 additional genotypes using two LC-MS/MS methods. Patients and methods CBS activity was measured in EDTA or heparin plasma using either a previously described or a newly developed LC-MS/MS method optimized for analysis of the reaction product, 3,3-(2)H2-cystathionine, as its butyl ester derivative. We analyzed plasma samples from 26 CBS-deficient patients with known genotypes and 57 controls. We developed a new LC-MS/MS method for simple and sensitive determination of CBS activity. Plasma CBS activity was low (i.e., 0.001-0.036 of the multiples of median control values, MoM) in patients homozygous for the prevalent Hispanic mutation c.572C>T (p.T191M) but was highly elevated (2.95 MoM) in a single patient...
Purine and pyrimidine disorders represent a heterogeneous group with variable clinical symptoms a... more Purine and pyrimidine disorders represent a heterogeneous group with variable clinical symptoms and low prevalence rate. In the last thirteen years, we have studied urine/plasma specimens from about 1600 patients and we have identified 35 patients: eight patients with adenylosuccinate lyase deficiency, eight patients with hypoxanthine-guanine phosphoribosyltransferase deficiency, one patient with purine nucleoside phosphorylase deficiency, ten patients with xanthine dehydrogenase deficiency, six patients with molybdenum cofactor deficiency and two patients with dihydropyrimidine dehydrogenase deficiency. Despite low incidence of these diseases, our findings highlight the importance of including the purine and pyrimidine analysis in the selective screening for inborn errors of metabolism in specialized laboratories, where amino acid and organic acid disorders are simultaneously investigated.
Recent years have seen great advances in our knowledge of congenital disorders of glycosylation (... more Recent years have seen great advances in our knowledge of congenital disorders of glycosylation (CDG), a clinically and biochemically heterogeneous group of genetic diseases caused by defects in the synthesis (CDG-I) or processing (CDG-II) of glycans that form glycoconjugates. This paper reports a new subtype of non-neurological CDG involving the impaired cytoplasmic biosynthesis of nucleotide sugars needed for glycan biosynthesis. A patient presented with muscle fatigue, elevated creatine kinase, growth hormone deficiency, and first branchial arch syndrome. These findings, together with the abnormal type II plasma transferrin isoform profile detected, was compatible with a CDG. Functional testing and clinical analyses suggested a deficiency in the interconversion of glucose-1-phosphate and glucose-6-phosphate catalyzed by phosphoglucomutase (PGM1), a defect previously described as glycogenosis type XIV (GSDXIV, MIM 612934). PGM1 activity in patient-derived fibroblasts was significantly reduced, as was the quantity of immunoreactive PGM1 protein (Western blot assays). Mutation analysis of PGM1 and subsequent functional analysis investigating transient expression of PGM1 in immortalized patient fibroblasts, followed by ex vivo splicing assays using minigenes, allowed the characterization of two novel pathogenic mutations: c.871G>A (p.Gly291Arg) and c.1144 + 3A>T. The latter represents a severe splicing mutation leading to the out-of-frame skipping of exon 7 and the formation of a truncated protein (p.Arg343fs). MALDI mass spectra of permethylated protein N-glycans from the patient's serum suggested a marked hypoglycosylation defect. The present findings confirm that, in addition to a rare muscular glycolytic defect, PGM1 deficiency causes a non-neurological disorder of glycosylation.
High concentrations of butyryl/isobutyrylcarnitine (C(4)-carnitine) in plasma with increase of et... more High concentrations of butyryl/isobutyrylcarnitine (C(4)-carnitine) in plasma with increase of ethylmalonic acid (EMA) in urine point to different genetic entities, and further investigations are required to differentiate the possible underlying defect. Here we report three unrelated cases, two neurologically affected and one asymptomatic, with this abnormal metabolite pattern due either to mutations in the ETHE1 gene or to a short-chain acyl-CoA dehydrogenase (SCAD) defect.
This paper describes a full detailed high performance liquid chromatography/tandem mass spectrome... more This paper describes a full detailed high performance liquid chromatography/tandem mass spectrometry method for the identification and quantification of human urine alpha-aminoadipic semialdehyde, biomarker of pyridoxine-dependent epilepsy. The ionization mode of the electrospray interface was negative and the metabolite was detected in the multiple reaction monitoring mode. Intra-day and inter-day laboratory precision were 4.64% and 7.30%, respectively, total run time was 3.5min. The calibration curve was linear between 0.25 and 10nmol with a correlation coefficient of the calibration line (R(2)≥0.9984); the limit of quantification was 0.25nmol within the control group. This simple, fast, high reproducible and robust procedure facilitates a rapid diagnosis of patients with pyridoxine-dependent epilepsy and can also be used to confirm the elevated urinary alpha-aminoadipic semialdehyde excretion in patients with other metabolic diseases as molybdenum cofactor and isolated sulphite oxidase deficiencies.
Background. Patients with inborn errors of metabolism (IEM) pose specific management challenges, ... more Background. Patients with inborn errors of metabolism (IEM) pose specific management challenges, considering their multisystem involvement. Among them, children and adults with organic acidemias (OA) and other disorders of the amino acid metabolism have a high risk for severe metabolic events that need to be recognized and promptly treated, and therefore require frequent clinical and biochemical evaluations. The novel highly pathogenic SARS-CoV2 virus appeared in Europe in the first trimester of 2020. This pandemic has a huge impact on the health care systems all over the world, interrupting the follow-up of many chronic diseases. For metabolic patients, travel to reference units may be reduced due to mobility restrictions but more importantly, attendance to medical facilities can be a risk of infection that can be a danger in itself but also trigger a metabolic decompensation.Methods. During the first coronavirus disease (COVID-19) outbreak in Spain from March to June 2020, we desi...
Mitochondrial fatty acid β-oxidation (FAO) contributes a large proportion to the body’s energy ne... more Mitochondrial fatty acid β-oxidation (FAO) contributes a large proportion to the body’s energy needs in fasting and in situations of metabolic stress. Most tissues use energy from fatty acids, particularly the heart, skeletal muscle and the liver. In the brain, ketone bodies formed from FAO in the liver are used as the main source of energy. The mitochondrial fatty acid oxidation disorders (FAODs), which include the carnitine system defects, constitute a group of diseases with several types and subtypes and with variable clinical spectrum and prognosis, from paucisymptomatic cases to more severe affectations, with a 5% rate of sudden death in childhood, and with fasting hypoketotic hypoglycemia frequently occurring. The implementation of newborn screening programs has resulted in new challenges in diagnosis, with the detection of new phenotypes as well as carriers and false positive cases. In this article, a review of the biochemical markers used for the diagnosis of FAODs is presen...
En el area de la tecnologia de los alimentos, las novedosas tecnicas de extraccion que se basan e... more En el area de la tecnologia de los alimentos, las novedosas tecnicas de extraccion que se basan en el empleo de dioxido de carbono supercritico poseen claras ventajas sobre aquellas consideradas convencionales. Con el fin de contribuir al avance sobre la aplicacion de esta tecnica junto con el desarrollo de nuevos productos de mayor calidad y el aprovechamiento de subproductos se planteo: la disminucion del contenido en colesterol de la grasa de la nata mediante la extraccion con CO2 supercritico, siendo las condiciones de 14,5 mpa a 40, 50 y 60 grados c las que producian el maximo rendimiento de extraccion (75%). Otro objetivo fue el fraccionamiento de la grasa lactea de la nata por el mismo metodo, observandose que era imprescindible el uso de soportes solidos (bolas de vidrio) para favorecer la maxima extraccion de los trigliceridos. Previamente se estimo la composicion de la grasa lactea identificandose 181 especies, algunas de ellas por primera vez. Asi mismo, se procedio al es...
Incidental findings on newborn screening (NBS) are results that are not the target of screening w... more Incidental findings on newborn screening (NBS) are results that are not the target of screening within a given NBS program, but rather are found as a result of the screening and resulting diagnostic workup for that target. These findings may not have an immediate clinical impact on the newborn, but are sometimes an additional benefit of NBS programs and may be considered secondary targets of NBS programs. This work describes four case reports that had incidental findings on the NBS, which eventually led to the diagnosis of another metabolic disease instead of the one that was initially suspected. The first case was a new defect in the cationic amino acid transporter-2 (CAT-2), which was oriented as an arginase-1 deficiency in the newborn. The second case was a maternal glutaric aciduria type 1 (GA-1) that mimicked a carnitine transporter deficiency in the newborn. The third report was a case of lysinuric protein intolerance (LPI), which appeared as high levels of citrulline on the N...
This review discusses the development of capillary electrophoresis with laser-induced detection a... more This review discusses the development of capillary electrophoresis with laser-induced detection and mass spectrometry techniques for the analysis of urinary oligosaccharides to screen for human oligosaccharidoses and related disorders. Capillary electrophoresis is suitable for the analysis of urinary oligosaccharides. It has a high resolution efficiency, and when it is coupled to a laser-induced fluorescence detector system, it offers an optimal analytical sensitivity. Mass spectrometry techniques have evolved as powerful tools for glycan analyses, are important tools for the analysis of oligosaccharide structures, and offer precise results, analytical versatility, very high sensitivity, high precision and high speed. Mass spectrometry is tolerant of mixtures and is a natural choice for the analysis of this class of molecules. The urine oligosaccharide profiles from healthy controls and patients diagnosed with different lysosomal storage diseases (fucosidosis, α-mannosidosis, GM1 ga...
Succinic semialdehyde dehydrogenase deficiency (gamma-hydroxybutyric aciduria) is a rare neuromet... more Succinic semialdehyde dehydrogenase deficiency (gamma-hydroxybutyric aciduria) is a rare neurometabolic disease caused by a deficiency in gamma-aminobutyric degradation, resulting in an increase in gamma-hydroxybutyric acid in biological fluids. The clinical spectrum is heterogeneous, including a variety of neurological manifestations and psychiatric symptoms. The treatment usually used is vigabatrin, but its clinical efficacy is under discussion. We present two affected siblings. The older brother was examined when he was 2.5 years old due to psychomotor and developmental delay, disturbances in motor coordination, axial hypotonia and language disability. His younger brother had mild axial hypotonia when 5 months old. Metabolic studies demonstrated a high plasma and urine concentration of gamma-hydroxybutyric acid. Mutation analysis of the gene ALDH5A1 confirmed the disease. After 1 year of treatment with low-doses of vigabatrin of the older patient, a decrease in gamma-hydroxybutyr...
Clinica chimica acta; international journal of clinical chemistry, 2015
Cystathionine β-synthase (CBS) is released into plasma from organs expressing this enzyme. Decrea... more Cystathionine β-synthase (CBS) is released into plasma from organs expressing this enzyme. Decreased plasma CBS activity has been demonstrated in CBS-deficient patients with 16 different genotypes. The aim of this study was to determine plasma CBS activity in patients carrying 11 additional genotypes using two LC-MS/MS methods. Patients and methods CBS activity was measured in EDTA or heparin plasma using either a previously described or a newly developed LC-MS/MS method optimized for analysis of the reaction product, 3,3-(2)H2-cystathionine, as its butyl ester derivative. We analyzed plasma samples from 26 CBS-deficient patients with known genotypes and 57 controls. We developed a new LC-MS/MS method for simple and sensitive determination of CBS activity. Plasma CBS activity was low (i.e., 0.001-0.036 of the multiples of median control values, MoM) in patients homozygous for the prevalent Hispanic mutation c.572C>T (p.T191M) but was highly elevated (2.95 MoM) in a single patient...
Purine and pyrimidine disorders represent a heterogeneous group with variable clinical symptoms a... more Purine and pyrimidine disorders represent a heterogeneous group with variable clinical symptoms and low prevalence rate. In the last thirteen years, we have studied urine/plasma specimens from about 1600 patients and we have identified 35 patients: eight patients with adenylosuccinate lyase deficiency, eight patients with hypoxanthine-guanine phosphoribosyltransferase deficiency, one patient with purine nucleoside phosphorylase deficiency, ten patients with xanthine dehydrogenase deficiency, six patients with molybdenum cofactor deficiency and two patients with dihydropyrimidine dehydrogenase deficiency. Despite low incidence of these diseases, our findings highlight the importance of including the purine and pyrimidine analysis in the selective screening for inborn errors of metabolism in specialized laboratories, where amino acid and organic acid disorders are simultaneously investigated.
Recent years have seen great advances in our knowledge of congenital disorders of glycosylation (... more Recent years have seen great advances in our knowledge of congenital disorders of glycosylation (CDG), a clinically and biochemically heterogeneous group of genetic diseases caused by defects in the synthesis (CDG-I) or processing (CDG-II) of glycans that form glycoconjugates. This paper reports a new subtype of non-neurological CDG involving the impaired cytoplasmic biosynthesis of nucleotide sugars needed for glycan biosynthesis. A patient presented with muscle fatigue, elevated creatine kinase, growth hormone deficiency, and first branchial arch syndrome. These findings, together with the abnormal type II plasma transferrin isoform profile detected, was compatible with a CDG. Functional testing and clinical analyses suggested a deficiency in the interconversion of glucose-1-phosphate and glucose-6-phosphate catalyzed by phosphoglucomutase (PGM1), a defect previously described as glycogenosis type XIV (GSDXIV, MIM 612934). PGM1 activity in patient-derived fibroblasts was significantly reduced, as was the quantity of immunoreactive PGM1 protein (Western blot assays). Mutation analysis of PGM1 and subsequent functional analysis investigating transient expression of PGM1 in immortalized patient fibroblasts, followed by ex vivo splicing assays using minigenes, allowed the characterization of two novel pathogenic mutations: c.871G>A (p.Gly291Arg) and c.1144 + 3A>T. The latter represents a severe splicing mutation leading to the out-of-frame skipping of exon 7 and the formation of a truncated protein (p.Arg343fs). MALDI mass spectra of permethylated protein N-glycans from the patient's serum suggested a marked hypoglycosylation defect. The present findings confirm that, in addition to a rare muscular glycolytic defect, PGM1 deficiency causes a non-neurological disorder of glycosylation.
High concentrations of butyryl/isobutyrylcarnitine (C(4)-carnitine) in plasma with increase of et... more High concentrations of butyryl/isobutyrylcarnitine (C(4)-carnitine) in plasma with increase of ethylmalonic acid (EMA) in urine point to different genetic entities, and further investigations are required to differentiate the possible underlying defect. Here we report three unrelated cases, two neurologically affected and one asymptomatic, with this abnormal metabolite pattern due either to mutations in the ETHE1 gene or to a short-chain acyl-CoA dehydrogenase (SCAD) defect.
This paper describes a full detailed high performance liquid chromatography/tandem mass spectrome... more This paper describes a full detailed high performance liquid chromatography/tandem mass spectrometry method for the identification and quantification of human urine alpha-aminoadipic semialdehyde, biomarker of pyridoxine-dependent epilepsy. The ionization mode of the electrospray interface was negative and the metabolite was detected in the multiple reaction monitoring mode. Intra-day and inter-day laboratory precision were 4.64% and 7.30%, respectively, total run time was 3.5min. The calibration curve was linear between 0.25 and 10nmol with a correlation coefficient of the calibration line (R(2)≥0.9984); the limit of quantification was 0.25nmol within the control group. This simple, fast, high reproducible and robust procedure facilitates a rapid diagnosis of patients with pyridoxine-dependent epilepsy and can also be used to confirm the elevated urinary alpha-aminoadipic semialdehyde excretion in patients with other metabolic diseases as molybdenum cofactor and isolated sulphite oxidase deficiencies.
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