glutarylcarnitine and glutaric-acid

Lysine is an essential amino acid, and inherited diseases of its metabolism therefore represent defects of lysine catabolism. Although some of these enzyme defects are not well described yet, glutaric aciduria type I (GA1) and antiquitin (2-aminoadipic-6-semialdehyde dehydrogenase) deficiency represent the most well-characterized diseases. GA1 is an autosomal recessive disorder due to a deficiency of glutaryl-CoA dehydrogenase. Untreated patients exhibit early onset macrocephaly and may present a neurological deterioration with regression and movement disorder at the time of a presumably "benign" infection most often during the first year of life. This is associated with a characteristic neuroimaging pattern with frontotemporal atrophy and striatal injuries. Diagnosis relies on the identification of glutaric and 3-hydroxyglutaric acid in urine along with plasma glutarylcarnitine. Treatment consists of a low-lysine diet aiming at reducing the putatively neurotoxic glutaric and 3-hydroxyglutaric acids. Additional therapeutic measures include administration of l-carnitine associated with emergency measures at the time of intercurrent illnesses aiming at preventing brain injury. Early treated (ideally through newborn screening) patients exhibit a favorable long-term neurocognitive outcome, whereas late-treated or untreated patients may present severe neurocognitive irreversible disabilities. Antiquitin deficiency is the most common form of pyridoxine-dependent epilepsy. α-Aminoadipic acid semialdehyde (AASA) and Δ-1-piperideine-6-carboxylate (P6C) accumulate proximal to the enzymatic block. P6C forms a complex with pyridoxal phosphate (PLP), a key vitamer of pyridoxine, thereby reducing PLP bioavailability and subsequently causing epilepsy. Urinary AASA is a biomarker of antiquitin deficiency. Despite seizure control, only 25% of the pyridoxine-treated patients show normal neurodevelopment. Low-lysine diet and arginine supplementation are proposed in some patients with decrease of AASA, but the impact on neurodevelopment is unclear. In summary, GA1 and antiquitin deficiency are the 2 main human defects of lysine catabolism. Both include neurological impairment. Lysine dietary restriction is a key therapy for GA1, whereas its benefits in antiquitin deficiency appear less clear.

Topics: 2-Aminoadipic Acid; Aldehyde Dehydrogenase; Amino Acid Metabolism, Inborn Errors; Arginine; Brain; Brain Diseases, Metabolic; Brain Diseases, Metabolic, Inborn; Carnitine; Epilepsy; Glutarates; Glutaryl-CoA Dehydrogenase; Humans; Lysine; Metabolic Diseases; Pyridoxal Phosphate; Pyridoxine

The impact of coronavirus disease-19 (COVID-19) on metabolic outcome in patients with inborn errors of metabolism has rarely been discussed. Herein, we report a case with an acute encephalopathic crisis at the course of COVID-19 disease as the first sign of glutaric aciduria type 1 (GA-1).. A 9-month-old patient was admitted with encephalopathy and acute loss of acquired motor skills during the course of COVID-19 disease. She had lethargy, hypotonia, and choreoathetoid movements. In terms of COVID-19 encephalopathy, the reverse transcription-polymerase chain reaction assay test for COVID-19 was negative in cerebral spinal fluid. Brain imaging showed frontotemporal atrophy, bilateral subcortical and periventricular white matter, basal ganglia, and thalamic involvement. Elevated glutarylcarnitine in plasma and urinary excretion of glutaric and 3-OH-glutaric acids was noted. A homozygote mutation in the glutaryl-CoA dehydrogenase gene led to the diagnosis of GA-1.. With this report, neurological damage associated with COVID-19 has been reported in GA-1 patients for the first time in literature.

Topics: Amino Acid Metabolism, Inborn Errors; Brain; Brain Diseases; Brain Diseases, Metabolic; Carnitine; COVID-19; COVID-19 Testing; Female; Genetic Testing; Glutarates; Glutaryl-CoA Dehydrogenase; Humans; Infant; Magnetic Resonance Imaging; Motor Skills; Movement Disorders; Muscle Hypotonia

The clinical, biochemical and genetic findings in two Slovak patients with glutaric aciduria type I (GAI) are presented.. GAI is a rare autosomal recessive neuro-metabolic disorder caused by deficiency of glutaryl-CoA dehydrogenase, which is involved in the catabolic pathways of lysine, hydroxylysine and tryptophan. This enzymatic defect gives rise to elevated levels of glutaric acid (GA), 3-hydroxyglutaric acid (3-OH-GA) and glutarylcarnitine (C5DC) in body fluids.. Biochemical and molecular-genetic tests were performed. Urinary organic acids were analysed by Gas Chromatography/Mass Spectrometry (GC/MS) and the entire coding region of the GCDH gene, including flanking parts, was sequenced.. We found the presence of typical metabolic profile and novel causal pathogenic variants in both GAI patients.. We present the first report of two Slovak patients with GAI, which differed in the clinical and biochemical phenotype significantly. They were diagnosed by two distinct approaches - selective and newborn screening. Their diagnosis was complexly confirmed by biochemical and later on molecular-genetic examinations. Though we agreed with a thesis that early diagnostics might positively influenced patient's health outcome, contradictory facts should be considered. Supposed extremely low prevalence of GAI patients in the general population and/or the existence of asymptomatic individuals with a questionable benefit of the applied therapeutic intervention for them lead to doubts whether the inclusion of disease into the newborn screening programme is justified well enough (Tab. 1, Fig. 3, Ref. 41).

Topics: Amino Acid Metabolism, Inborn Errors; Base Sequence; Brain Diseases, Metabolic; Carnitine; Early Diagnosis; Female; Gas Chromatography-Mass Spectrometry; Genotype; Glutarates; Glutaryl-CoA Dehydrogenase; Humans; Infant, Newborn; Male; Mutation, Missense; Phenotype; Sequence Analysis; Slovakia

Azaspiracid (AZA) poisoning was unknown until 1995 when shellfish harvested in Ireland caused illness manifesting by vomiting and diarrhoea. Further in vivo/vitro studies showed neurotoxicity linked with AZA exposure. However, the biological target of the toxin which will help explain such potent neurological activity is still unknown. A region of Irish coastline was selected and shellfish were sampled and tested for AZA using mass spectrometry. An outbreak was identified in 2010 and samples collected before and after the contamination episode were compared for their metabolite profile using high resolution mass spectrometry. Twenty eight ions were identified at higher concentration in the contaminated samples. Stringent bioinformatic analysis revealed putative identifications for seven compounds including, glutarylcarnitine, a glutaric acid metabolite. Glutaric acid, the parent compound linked with human neurological manifestations was subjected to toxicological investigations but was found to have no specific effect on the sodium channel (as was the case with AZA). However in combination, glutaric acid (1 mM) and azaspiracid (50 nM) inhibited the activity of the sodium channel by over 50%. Glutaric acid was subsequently detected in all shellfish employed in the study. For the first time a viable mechanism for how AZA manifests itself as a toxin is presented.

Topics: Animals; Bivalvia; Carnitine; Cell Line; Cell Line, Tumor; Disease Outbreaks; Foodborne Diseases; Glutarates; HEK293 Cells; Humans; Marine Toxins; Shellfish; Sodium Channels; Spiro Compounds

We report two women with glutaric acidemia type I in whom the diagnosis was unsuspected until a low carnitine level was found in their newborn children. Both mothers had low carnitine in plasma. In the first, organic acid analysis was only done after fibroblast studies revealed normal carnitine uptake. Having learned from the first family, organic acid analysis was done immediately in the mother of family 2. In both, the plasma acylcarnitine profile was normal but both excreted the metabolites typical of their disorder. One of the women was a compound heterozygote for distinct mutations in the glutaric acid dehydrogenase gene, whereas the second was either homozygous or hemizygous for a mutation in Exon 6 of the gene.

Topics: Amino Acid Metabolism, Inborn Errors; Carnitine; Female; Glutarates; Glutaryl-CoA Dehydrogenase; Humans; Infant, Newborn; Mutation; Neonatal Screening

Glutaric acidemia type I (GA-1) is a progressive neurodegenerative inborn error of metabolism that typically manifests acutely in infants during an intercurrent illness. The diagnosis is established biochemically by the detection of glutaric acid and 3-hydroxy glutaric acid in urine and glutarylcarnitine in plasma. However, some patients excrete only small amounts of glutaric acid and may be overlooked, especially if the plasma concentration of glutarylcarnitine is not elevated. To test the hypothesis that measuring the excretion of glutarylcarnitine may improve the recognition of GA-1 patients without significant glutaric aciduria, urine glutarylcarnitine was analyzed in 14 cases. Five of them lacked significant glutaric aciduria, 9 (of 10 available) had a normal plasma glutarylcarnitine concentration. As controls, we also evaluated 54 subjects with glutaric aciduria secondary to other causes (16-7509 mmol/mol creatinine; reference range: <15; no significant amounts of 3-hydroxy glutaric acid detectable). The excretion of glutarylcarnitine was significantly elevated in all GA-1 patients (14-522 mmol/mol creatinine; reference range: <5.2) and in none of the controls with glutaric aciduria. These findings suggest that the urinary excretion of glutarylcarnitine is a specific biochemical marker of GA-1 which could be particularly useful in the work up of patients with suggestive clinical manifestations but without glutaric aciduria and with normal plasma acylcarnitine profiles.

Topics: Carnitine; Case-Control Studies; Glutarates; Humans

Glutaryl-CoA dehydrogenase deficiency (GA-I) is associated with the onset of irreversible, disabling dystonia between 3 and 18 months of age. Presymptomatic identification and treatment can prevent the devastating disability associated with this disorder. We report the retrospective analysis of the newborn blood spot of an affected child with a low excretor phenotype. The level of glutarylcarnitine was below the newborn screening program cut-off. This suggests that some cases of GA-I may be missed by newborn screening by tandem mass spectrometry.

Topics: Carnitine; Cells, Cultured; Fibroblasts; Glutarates; Glutaryl-CoA Dehydrogenase; Humans; Infant, Newborn; Mass Spectrometry; Neonatal Screening; Retrospective Studies

Glutaryl-CoA dehydrogenase (GCDH) deficiency causes glutaric academia type I (GA-I), an inborn error of metabolism that is characterized clinically by dystonia and dyskinesia and pathologically by neural degeneration of the caudate nucleus and putamen. We report a case of GA-I in a 4-year-old boy. Analysis of blood acylcarnitines by tandem mass spectrometry (MS/MS) revealed a high concentration of glutarylcarnitine in the blood (0.59 microM). Organic acid analysis of urine via gas chromatography mass spectrometry revealed glutaric acid and 3-hydroxyglutaric acids. In order to search for mutations, the GCDH gene of the patient and his parents were amplified by polymerase chain reaction and subjected to direct sequencing. Two mutations were detected in the patient's GCDH gene. One was located in exon 7 (T713C), which caused a codon 238 leucine to proline substitution; the other was located in intron 10 (IVS10-2 A-to-C), and caused a splicing variation in intron 10 and exon 11. Genetic amniocentesis was requested when the patient's mother became pregnant again, but the fetus did not carry any mutation. Tandem mass spectrometry was successfully used to make the diagnosis of GA-I in this case via identification of genetic mutation. If GA-I can be diagnosed in the early onset or presymptomatic stage, effective therapy would reduce sequelae.

Topics: Amino Acid Metabolism, Inborn Errors; Carnitine; Child, Preschool; Glutarates; Glutaryl-CoA Dehydrogenase; Humans; Male; Mutation; Oxidoreductases Acting on CH-CH Group Donors

The neurometabolic disorder glutaryl-CoA dehydrogenase (GCDH) deficiency is biochemically characterised by an accumulation of the marker metabolites 3-hydroxyglutaric acid, glutaric acid, and glutarylcarnitine. If untreated, the disease is complicated by acute encephalopathic crises, resulting in neurodegeneration of vulnerable brain regions, in particular the putamen. 3-hydroxyglutaric acid is considered the major neurotoxin in this disease. There are only preliminary data concerning glutaric acid concentrations in the brains of affected children and the distribution of 3-hydroxyglutaric acid and glutarylcarnitine has not been described. In the present study, we investigated post mortem the distribution of 3-hydroxyglutaric and glutaric acids as well as glutarylcarnitine in 14 different brain regions, internal organs, and body fluids (urine, plasma, cerebrospinal fluid) in a 14-year-old boy. 3-Hydroxyglutaric acid showed the highest concentration (62 nmol/g protein) in the putamen among all brain areas investigated. The glutarylcarnitine concentration was also highest in the putamen (7.1 nmol/g protein). We suggest that the regional-specific differences in the relative concentrations of 3-hydroxyglutaric acid contribute to the pattern of neuronal damage in this disease. These results provide an explanatory basis for the high vulnerability of the putamen in this disease, adding to the strong corticostriatal glutamatergic input into the putamen and the high excitotoxic susceptibility of neostriatal medium spiny neurons.

Topics: Acidosis; Acute Disease; Adolescent; Anticonvulsants; Atrophy; Brain; Carnitine; DNA Mutational Analysis; Fatal Outcome; Gas Chromatography-Mass Spectrometry; Gene Expression; Glutarates; Glutaryl-CoA Dehydrogenase; Humans; Male; Muscle Hypotonia; N-Methylaspartate; Oxidoreductases Acting on CH-CH Group Donors; Point Mutation; Putamen; Spasm; Vigabatrin

Topics: Amino Acid Metabolism, Inborn Errors; Carnitine; Child; Child, Preschool; Gas Chromatography-Mass Spectrometry; Glutarates; Glutaryl-CoA Dehydrogenase; Humans; Infant; Oxidoreductases; Oxidoreductases Acting on CH-CH Group Donors; Spectrometry, Mass, Fast Atom Bombardment

The urinary acylcarnitine profiles of two mothers whose first children were diagnosed to have glutaric aciduria type 2 (multiple acyl-CoA dehydrogenation deficiency, electron transfer flavoprotein (ETF) deficiency) were analysed in the second pregnancy. Large volumes of tigrylcarnitine and isovalerylcarnitine and a little glutarylcarnitine were detected. Each fetus was also diagnosed to be abnormal by enzyme activity and immunoassay of ETF protein. The acylcarnitines in the mothers' urine disappeared in 1 week after labour or artificial abortion. Acylcarnitines were never detected in the urine of controls.

Topics: Abortion, Induced; Amino Acid Metabolism, Inborn Errors; Amniotic Fluid; Carnitine; Female; Glutarates; Humans; Pregnancy; Prenatal Diagnosis

A technique for the identification of glutarylcarnitine in urine from a patient with glutaric aciduria type 1 is described. The patient's urine sample was partially purified using an anion exchange column and analyzed by a carboxylic acid analyzer fitted with an ODS reverse-phase column. The chromatogram of the patient's urine sample revealed 3 different peaks, which corresponded respectively to those of carnitine with amino acids, acetylcarnitine and glutarylcarnitine. Following hydrolysis of the sample, the chromatogram had no peaks of acetylcarnitine and glutarylcarnitine but had remarkably amplified peaks of carnitine, acetic acid and glutaric acid. The eluent fraction of glutarylcarnitine from the non-hydrolyzed sample was hydrolyzed and analyzed again. It no longer had the glutarylcarnitine peak on the chromatogram, but had only two separate peaks of carnitine and glutaric acid. This technique simplifies the identification of glutarylcarnitine, in that it requires only removal of organic acids for preparation of samples, and does not require radioisotope or mass spectrometry.

Topics: Acetylcarnitine; Amino Acid Metabolism, Inborn Errors; Autoanalysis; Carboxylic Acids; Carnitine; Chromatography; Glutarates; Humans; Infant; Male