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Background Glutaric acidemia is a type of multiple acyl-coenzyme A dehydrogenase deficiency, an inborn error in fatty acid metabolism. In patients with glutaric acidemia, during the perioperative period, prolonged fasting, stress, and pain have been identified as risk factors for the induction of metabolic derangement. This report describes the surgical and anesthetic management of a patient with glutaric acidemia. Case presentation A 56-year-old male patient with glutaric acidemia type 2 underwent a series of surgeries. During the initial off-pump coronary artery bypass surgery, the patient developed renal failure due to rhabdomyolysis upon receiving glucose at 2 mg/kg/min. However, in the second laparoscopic cholecystectomy, rhabdomyolysis was avoided by administering glucose at 4 mg/kg/min. Conclusions To avoid catabolism in patients with glutaric acidemia, appropriate glucose administration is important, depending on the surgical risk.

Multiple acyl-CoA dehydrogenase deficiency (MADD), also known as glutaric acidemia or glutaric aciduria type II, can be caused by mutations in three different genes (ETFA, ETFB, ETFDH), which are all involved in electron transfer in the mitochondrial respiratory chain. In most patients MADD is caused by mutations in the ETFDH gene (Table 63.1), encoding the electron transfer flavoprotein dehydrogenase. MADD results in large excretion of glutaric, lactic, ethylmalonic, butyric, isobutyric, 2-methyl-butyric, and isovaleric acids.

The analysis of characteristic urinary acidic markers such as glutaric, 3-hydroxyglutaric, 2-hydroxyglutaric, adipic, suberic, sebacic, ethylmalonic, 3-hydroxyisovaleric and isobutyric acid constitutes the recommended follow-up testing procedure for glutaric acidemia type 1 (GA-1) and type 2 (GA-2). The goal of the work herein presented is the development of a fast and simple method for the quantification of these biomarkers in human urine. The proposed analytical approach is based on the use of solid phase microextraction (SPME) combined with gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS) afterward a rapid derivatization of acidic moieties by propyl chloroformate, propanol and pyridine. Trueness and precision of the proposed protocol, tested at 5, 30 and 80mgl-1, provided satisfactory values: recoveries were in the range between 72% and 116% and the relative standard deviations (RSD%) were between 0.9% and 18% (except for isobutyric acid at 5mgl-1). The LOD values achieved by the proposed method ranged between 1.0 and 473μgl-1.

The first crystal structure is reported of a glutaryl-CoA dehydrogenase in the apo state without flavin adenine dinucleotide cofactor bound. Additional structures with small molecules complexed in the catalytic active site were obtained by fragment-based screening., Glutaric acidemia type 1 is an inherited metabolic disorder which can cause macrocephaly, muscular rigidity, spastic paralysis and other progressive movement disorders in humans. The defects in glutaryl-CoA dehydrogenase (GCDH) associated with this disease are thought to increase holoenzyme instability and reduce cofactor binding. Here, the first structural analysis of a GCDH enzyme in the absence of the cofactor flavin adenine dinucleotide (FAD) is reported. The apo structure of GCDH from Burkholderia pseudomallei reveals a loss of secondary structure and increased disorder in the FAD-binding pocket relative to the ternary complex of the highly homologous human GCDH. After conducting a fragment-based screen, four small molecules were identified which bind to GCDH from B. pseudomallei. Complex structures were determined for these fragments, which cause backbone and side-chain perturbations to key active-site residues. Structural insights from this investigation highlight differences from apo GCDH and the utility of small-molecular fragments as chemical probes for capturing alternative conformational states of preformed protein crystals.

Synaptosomes and plasma membrane preparations from brain of 30-day-old rats were incubated with glutaric acid at final concentrations ranging from 10 nM to 1 mM for the determination of glutamate uptake and binding, respectively. [3H]Glutamate uptake into synaptosomes was inhibited by approximately 50% by 1 mM glutaric acid, corresponding to the concentration found in brain of glutaric acidemic children. In addition, in the presence of extracellular Na+ concentrations, the same dose of glutaric acid decreased by about 30% [3H]glutamate binding to brain plasma membranes. The results indicate that the inhibition of both glutamate uptake into synaptosomes and glutamate binding to plasma synaptic membranes by the metabolite could result in elevated concentrations of the excitatory neurotransmitter in the synaptic cleft, potentially causing excitotoxicity to neural cells, a fact that may be related to the brain damage characteristic of glutaric acidemia type I.

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.

Glutaric acidemia type I (GA-I) is an inherited metabolic disease characterized by striatal degeneration, seizures, and accumulation of glutaric acid (GA). Considering that GA impairs energy metabolism and induces reactive species generation, we investigated whether the acute administration of creatine, an amino acid with antioxidant and ergogenic properties, protects against the seizures and neurochemical alterations (inhibition of Na + ,K + -ATPase and increased protein carbonylation) induced by the intrastriatal injection of GA (4 μmol/striatum). We also investigated whether creatine protected against the GA-induced inhibition of glutamate uptake in vitro . Creatine administration (300 mg/kg, p.o.) decreased seizures (evidenced by electrographic changes), protein carbonylation and Na + ,K + -ATPase inhibition induced by GA. However, creatine, at a dose capable of fully preventing GA-induced protein carbonylation (50 and 150 mg/kg, p.o.), did not prevent convulsions and Na + ,K + -ATPase inhibition, suggesting that the anticonvulsant activity of creatine in this experimental model is not related to its antioxidant action. Creatine also protected against the GA-induced inhibition of l -[ 3 H]glutamate uptake in synaptosomes, suggesting that creatine may reduce the deleterious effects of GA by maintaining glutamate uptake in the synaptic cleft. Therefore, considering that creatine significantly attenuates the deleterious effects of GA assessed by behavioral and neurochemical measures, it is plausible to propose the use of this amino acid as an adjuvant therapy in the management of glutaric acidemia.

Background Disorders of organic acid (OA) metabolism are generally detected by qualitative analysis of urine organic acids by gas chromatography/mass spectrometry (GC/MS) which was well established in developed countries since 1980s. Confirmation of the diagnosis of organic acid disorders by OA analysis, enzyme analysis and molecular study is a difficult task in developing countries. Methods During 2001–2004, we had analysed 442 urine samples in 365 patients and identified 12 cases of organic acid disorders. Results We identified the following disorders: alkaptonuria (ALK) = 1, isovaleric acidemia (IVA) = 3, propionic acidemia (PA) = 2, methylmalonic acidemia (MMA) = 3, glutaric aciduria, type I (GA-I) = 1, multiple carboxylase deficiency (MCD) = 1, and glutaric acidemia, type II (GA-II) = 1. Conclusions OA disorders had never been diagnosed in Thailand before, until GC/MS technology was introduced to Thailand in 2001. Urine OA analysis also provided a diagnostic clue to other inborn errors of metabolism including amino acid disorders, urea cycle disorders, disorders of carbohydrate metabolism, and mitochondrial fatty acid oxidation disorders. Since then, we were able to diagnose numerous disorders, which led to prompt treatment and better outcome in our patients.

Glutaric acidemias comprise different disorders resulting in an increased urinary excretion of glutaric acid. Glutaric acidemia type 1 (GA-1) is an autosomal recessive disorder of lysine, hydroxylysine, and tryptophan metabolism caused by deficiency of glutaryl-CoA dehydrogenase. It results in the accumulation of 3-hydroxyglutaric and glutaric acid. Affected patients can present with brain atrophy and macrocephaly and with acute dystonia secondary to striatal degeneration in most cases triggered by an intercurrent childhood infection with fever between 6 and 18 months of age. This disorder can be identified by increased glutaryl (C5DC) carnitine on newborn screening. Urine organic acid analysis indicates the presence of excess 3-OH-glutaric acid, and urine acylcarnitine profile shows glutaryl carnitine as the major peak. Therapy consists in carnitine supplementation to remove glutaric acid, a diet restricted in amino acids capable of producing glutaric acid, and prompt treatment of intercurrent illnesses. Early diagnosis and therapy reduce the risk of acute dystonia in patients with GA-1.

For the past 30 years, neonatal screening programs have been performed largely by using the bacterial inhibition assays developed by Dr Robert Guthrie. These programs focused on a small number of diseases such as phenylketonuria and maple syrup urine disease and involved one test for each disease. During the same period many new diseases were discovered, such as organic acidemias and fatty acid oxidation defects, and they presented a diagnostic challenge to biochemical laboratories. Different mass spectrometric approaches have been the main tools for the diagnosis; however, each has its own limitation. Recently, electrospray tandem mass spectrometry (MS/MS) has provided an alternative automated high throughput, specific, and broad-spectrum approach to screening for a relatively large number of disorders, including those covered by bacterial inhibition assays tests. By using specific scan functions, a large number of amino acids and acylcarnitines in blood spots are quantified in 2 minutes analytical time. A new scan function is described here for quantification and screening for argininosuccinic acid in blood spots, which is a key metabolite in the diagnosis of argininosuccinase deficiency. We describe the results of a 3-year tandem MS/MS-based neonatal study that was performed in our newborn population. We screened 27,624 blood spots and identified 20 cases yielding a frequency of 1:1,381. No false-negative cases were identified, but several false-positive cases were eliminated by repeat analysis by MS/MS of blood or by other means. We also used MS/MS analysis of urine or blood either for confirmation of initial positive results or for follow-up of treatment, such as in glutaric acidemia, citrullinemia, argininosuccinase deficiency, and biopterin-dependent phenylketonuria.

Two siblings who were found to have deficiency of glutaryl-CoA dehydrogenase were identified by the presence of large amounts of 3-hydroxyglutaric acid in the urine. Patients with this disease, termed glutaric acidemia or glutaric acidemia Type I, usually present with large amounts of glutaric acid in the urine, and amounts of 3-hydroxyglutaric acid found are less. Patients were ataxic and dystonic. Intelligence was normal. 3-Hydroxyglutaric acid in the urine was quantified by organic acid analysis via gas chromatography mass spectrometry (GCMS) and by stable isotope-dilution (internal standard) GCMS. Glutaryl-CoA dehydrogenase activity in cultured fibroblasts was found to be 2% of the control level. The nature of the mutations was identified, and both patients were found to be compound heterozygotes for R227P, which changed an arginine to a proline, and E365K, which changed a glutamate to a lysine.

The effect of intrastriatal administration of glutaric acid (GTR), a metabolite that accumulates in glutaric acidemia type I (GA-I), on the behavior of adult male rats was investigated. After cannula placing, rats received unilateral intrastriatal injections of GTR buffered to pH 7.4 with NaOH or NaCl. GTR induced rotational behavior toward the contralateral side of injection and clonic convulsions in a dose-dependent manner. Rotational behavior was prevented by intrastriatal preadministration of DNQX and muscimol, but not by the preadministration of MK-801. Convulsions were prevented by intrastriatal preinjection of muscimol. This study provides evidence for a participation of glutamatergic non-NMDA and GABAergic mechanisms in the GTR-induced behavioral alterations. These findings may be of value in understanding the physiopathology of the neurological dysfunction in glutaric acidemia.

Detection and diagnostic confirmation of the mild variants of glutaric acidemia, type II (GAII), also termed ethylmalonic-adipic aciduria, and short chain acyl-CoA dehydrogenase deficiency (SCAD) and its variants are problematic and challenging at both the clinical, biochemical and molecular levels. The mild variants of GAII result from partial deficiencies of either electron transfer flavoprotein or its dehydrogenase and have highly variable clinical presentations and often ephemeral metabolite excretion. Direct assay of these latter two enzymes is difficult and performed at only a few laboratories worldwide. The clinical, biochemical, enzymatic, and molecular variation in SCAD is great and complicated by the presence of two common allelic variants, 625G/A and 511C/T, whose effects on enzymatic activities are not fully understood. Quantitation of urine organic acids, plasma acyl-camitines and urinary acyl-glycines may not suffice to clearly identify patients with these disorders due to variations in clinical status, substrate flux into the partially impaired pathways, and genetic heterogeneity. Therefore, we have modified an existing radioHPLC method for analysis of acyl-3H-carnitine esters in skin fibroblasts to optimize detection of these disorders (Schmidt-Sommerfeld, et al. Pediatr.Res, 44:210, 1998). Incubating fibroblasts with the branched-chain amino acids, leucine, isoleucine and valine, as well as palmitale, improves detection of the mild GAII variants; the propionyl-carnitine to isovaleryl/α-methyl butyryl-carnitine ratio is a very sensitive index of impaired dehydrogenation of the branched chain acyl-CoAs. For SCAD and its variants, butyryl-carnitine content is a very sensitive measure of SCAD-mediated butyryl-CoA dehydrogenation in intact cells. In normal cells, butyryl-carnitine content is less than 2% of total cellular acyl-camitine content, while it ranges from 10 to 25% in well defined SCAD cases lacking enzyme activity, antigen and harboring two pathogenetic mutations. In addition, we are routinely identifying patients who have clearly impaired SCAD activity, as judged by fibroblast butyryl-carnitine accumulations of 4 to 8%, who probably represent genetic compounds for the 625A/G and 511C/T variant alleles and/or other pathogenetic mutations. RadioHPLC analysis of fibroblast acyl-carnitines permits uniform, optimal challenging of the metabolic pathways in question, while minimizing the metabolite variation seen in plasma and urine analyses from patients with varying clinical, metabolic and molecular conditions. It is an important adjunct to the laboratory diagnosis of the fatty acid oxidation disorders.

A19-year-old woman with mild myopathie symptoms from age 6 and fasting intolerance presented with a Reye-like syndrome and a myopathy. Investigations disclosed a lipid storage myopathy, type II glutaric acidemia, and carnitine deficiency in skeletal muscle. Riboflavin and carnitine treatment corrected the metabolic abnormalities and she improved clinically. She later died from pulmonary complications secondary to aspiration. Subsequent studies established electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO) deficiency (fibroblast ETF:QO activity was 2.9 mU/mg, normal range is 14.1 ± 3.8 mU/mg) as the cause of her illness. This is the first documented case of ETF:QO diagnosed in an adult.

Studies are reported on two siblings with a neurodegenerative disorder, glutaric aciduria and glutaric acidemia. The glutaric aciduria was increased by oral administration of l -lysine, which is metabolized through glutaryl-CoA, and decreased by lowering protein intake. The metabolism of [1,5-14C] glutaryl-CoA was deficient in the peripheral leukocytes of the patients. The results are compatible with an inherited deficiency of glutaryl-CoA dehydrogenase. It is speculated, but not proved, that the biochemical abnormality is causally related to the central nervous system dysfunction.

Glutaric acidemia, type I, is an organic acidemia associated with a progressive neurologic disorder. 1 By 1 year of age, affected individuals generally have recurrent episodes of vomiting and lethargy associated with metabolic acidosis. Progressive neurologic defici ts include dysarthria, dystonia, and choreoathetosis. Most affected Children are also mentally retarded. The presumptive diagnosis of GA-I is made by gas chromatography-mass spectrometry of urine revealing peaks of glutaric acid and its principal metabolites 3-OH-glutarate and glutaconate. The enzyme deficiency, glutaryl CoA dehydrogenase, is demonstrable in leukocytes, fibroblasts, and hepatocytes. 2 Therapeutic approaches have included low-protein diets and diets low in tryptophan and lysine, the precursors of glutaryl CoA. 3 Riboflavin (as flavin adenine dinucleotide), a cofactor of glutaryl CoA dehydrogenase, has been given to enhance residual enzyme activity? L-Carnitine has been used to stimulate the formation and excretion of shortchain acylcarnitine derivatives of glutaric acid. 4 Finally, because of evidence of inhibition of synthesis of G A B A by glutaric acid and the presence of decreased G A B A in brains of affected individuals, the G A B A analog baclofen has been given) With these techniques, progression of symptoms has been arrested in a number of cases but little clinical improvement has resulted? -8 The present report concerns a boy with GA-I who had progressive "dystonic cerebral palsy" associated with basal ganglia degeneration and who responded to riboflavin and L-carnitine therapy with evidence of biochemical and clinical improvement.

Quantitation of 2-ketoglutarate in urine as its O-trimethylsilyl-quinoxalinol derivative by gas chromatography—chemical ionization mass spectrometry is described. This technique, with ammonia as reactant gas, produces no fragmentation and allows only the detection of the protonated molecular ion. It gives the greatest known sensitivity, and could be applied to the determination of urinary 2-ketoglutarate in normal children and in various metabolic disorders, such as dihydrolipoyl dehydrogenase defect, pyruvate carboxylase deficiency and type I glutaric acidemia.

A boy with glutaric acidemia had psychomotor retardation first noted at age 6 months, recurrent metabolic acidosis, and a progressive quadriparesis with choreoathetosis. He died at age 3 1/2 years. Cultured skin fibroblasts lacked glutaryl-CoA dehydrogenase activity. There was a biochemical, but not a clinical, response to dietary restriction of lysine and tryptophan. The caudate and putamen of the brain showed severe loss of nerve cells and fibers with proliferation of astrocytes, as well as markedly reduced gamma-aminobutyric acid and glutamate decarboxylase activity.

Glutaric acid was elevated in plasma (0.1-0.6 mg %;normal = undetected), urine (5 gm/gm creatinine;normal=undetected),and CSF (0.25 mg %;normal=undetected) of two siblings, a 1½ year old girl and a 7½ year old boy. Both have a neurodegenerative disorder characterized by initial normalcy followed by progressive deterioration to opisthotonus and posturing. Recurrent metabolic acidemia was present in the male. One sibling has neither glutaric acidemia nor neurologic dysfunction, and the parents deny consanguinity. Glutaryl-CoA is an intermediate in the metabolism of L-lysine, L-tryptophan, and hydroxy-L-lysine, being further metabolized through glutaconyl-CoA to crotonyl-CoA. Oral administration of L-lysine augmented the glutaric aciduria; L-valine did not. Decreasing protein intake from 4.1 to 1.6 gm/kg/day decreased glutaric acid excretion from 5 to 2 gm/gm creat. The metabolism of glutaric acid-l,5-14C in peripheral leucocytes and cultured fibroblasts was normal. If inherited, transmission may be as an autosomal recessive trait; carriers cannot be differentiated easily from controls by lysine loading. It is speculated that (1) the disorder is due to a block at the level of glutaryl-CoA dehydrogenase, and (2) that CNS dysfunction may relate to inhibition by glutaric acid of transport or metabolism of glutamic acid.

Glutaric acidemia (GA-1) is an autosomal recessive disorder of lysine, hydroxylysine,and tryptophan metabolism caused by deficiency of glutaryl-CoA dehydrogenase. It results in the accumulation of 3-hydroxyglutaric and glutaric acid. Affected patients can present with brain atrophy and macrocephaly and with acute dystonia secondary to striatal degeneration in most cases triggered by an intercurrent childhood infection with fever between 6 and 18 months of age. The most common animal model of GA-1 is GCDH deficient mouse. We are trying to establish a new cell model of GA-1 to study the mechanism of neurotoxicity and for the future establishment of the new animal model. Three Gcdh shRNA sequences were recombinated to the lentivirus vector carring the GFP reporter gene. And the Gcdh-shRNA vector with the highest knock-down efficiecy was transfected into the primary striatial neuron cells. Real-time PCR and Western Bot showed the knock-down efficiecy was about 65%. And compared with the control group, the cells transfected with Gcdh shRNA vector shrinked obviously and gathered together, the neurites disappeared, and cell debris increased significantly. Hoechst staining of the nucleus showed the increased apoptotic rate in the knock-down group. MTT indicated the decreased mitochondrial function after Gcdh shRNA interference. These results suggest that Gcdh shRNA interference in rat primary stiatial neuron cells could increase the apoptotic rate, which could due to the activation of mitochondria mediated apoptosis, tiggered by the dysfunction of the mitochondria.