Fatal hyperammonaemia in argininosuccinic aciduria following enflurane anaesthesia.
Explore the source record for details and available documents.
Adolescent↗
SEARCH · Search PubMed
Results for “AMINO ACIDURIA”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Use of proton nuclear magnetic resonance spectroscopy in detection and study of organic acidurias.
We used high-resolution proton nuclear magnetic resonance spectroscopy to detect, identify, and study the major normal and abnormal organic acid metabolites in urine from patients with propionic acidemia, methylmalonic aciduria, branched-chain ketoaciduria, isovaleric acidemia, and glutaric aciduria type I. Characteristic and diagnostic spectra were obtained at 400 MHz for each disorder in all the patients studied and neutral and basic compounds, including amino acids and acylcarnitines, were also detected. The technique is rapid (10 min) and requires small samples (0.5 mL) and no preliminary extraction or derivative preparation. We believe that it is particularly suitable for the rapid and acute diagnosis of inborn errors of metabolism, especially the organic acidurias, and for acute pediatric clinical care, when rapid monitoring of major metabolic alterations is required in a time scale suitable to influence directly and immediately the therapy of the patients concerned.
Amino Acid Metabolism, Inborn Errors↗
Homozygous nonsense mutation in the MCEE gene and siRNA suppression of methylmalonyl-CoA epimerase expression: a novel cause of mild methylmalonic aciduria.
Methylmalonyl-CoA epimerase (MCE) catalyzes the interconversion of D- and L-methylmalonyl-CoA in the pathway responsible for the degradation of branched chain amino acids, odd chain-length fatty acids, and other metabolites. Despite the occurrence of metabolic disorders in the enzymatic step occurring immediately upstream of MCE (propionyl-CoA carboxylase) and downstream of MCE (adenosylcobalamin-dependent methylmalonyl-CoA mutase), no disease-causing mutations have been described affecting MCE itself. A patient, formerly identified as belonging to the cblA complementation group of vitamin B12 disorders but lacking mutations in the affected gene, MMAA, was tested for mutations in the MCEE gene. The patient's fibroblasts had normal levels of adenosylcobalamin compared to controls, whereas other cblA cell lines typically had reduced levels of the cofactor. As well, this patient had a milder form of methylmalonic aciduria than usually observed in cblA patients. The patient was found to be homozygous for a c.139C>T (p.R47X) mutation in MCEE by sequence analysis that was confirmed by restriction digestion of PCR products. One sibling, also with mild methylmalonic aciduria, was homozygous for the mutation. Both parents and one other sibling were heterozygous. A nearby insertion polymorphism, c.41-160_161insT, heterozygous in both parents, showed the wild-type configuration on the mutant alleles. To assess the impact of isolated MCE deficiency in cultured cells, HeLa cells were transfected with a selectable vector containing MCEE-specific small interfering RNA (siRNA) to suppress gene expression. The reduced level of MCEE mRNA resulted in the reduction of [14C]-propionate incorporation into cellular macromolecules. However, siRNA only led to a small reduction in pathway activity, suggesting that previously postulated non-enzymatic conversion of D- to L-methylmalonyl-CoA may contribute to some flux through the pathway. We conclude that the patient's MCEE defect was responsible for the mild methylmalonic aciduria, confirming a partial requirement for the enzymatic activity in humans.
Cell Culture Techniques↗
Genetic approach to prenatal diagnosis in urea cycle defects.
OBJECTIVE: To demonstrate the feasibility of prenatal diagnosis by molecular genetics in all urea cycle defects in order to improve and standardize the current approaches. METHODS: Deceased index patients who had suffered from a urea cycle disorder were investigated for mutations of the biochemically most likely affected gene. If no material of index patients was available, parental DNA was studied for obligate carrier status. Fetal cells of 15 pregnancies, either chorionic villi or amniotic fluid cells, were used for direct sequence analysis of the respective mutations. Thirteen families were investigated, of which two were affected by N-acetylglutamate synthase deficiency, four by carbamoylphosphate synthetase 1 deficiency, one by ornithine transcarbamylase deficiency, three by argininosuccinate synthetase deficiency, two by argininosuccinate lyase deficiency, and one by arginase deficiency. RESULTS: Molecular genetics allowed the determination of the fetal status in all cases. Besides 14 known mutations, we detected the novel mutation c.544delC of the N-acetylglutamate synthase gene, the novel missense mutation c.721G>A (E241K) of the argininosuccinate lyase gene, and the novel double mutated allele comprising the known mutation c.703G>A (G235R) and the novel insertion c.712ins[GGACC](2) (254X) of the arginase 1 gene. CONCLUSION: Direct genetic analysis of chorionic villi or amniotic fluid cells is feasible, fast, and specific, and can be regarded as the method of choice for prenatal diagnosis in urea cycle disorders.
Acetyltransferases↗
An investigation of argininosuccinic acid anhydrides in argininosuccinic acid lyase deficiency by 1H-NMR spectroscopy.
Argininosuccinate (ASA) is excreted in large amounts in the urine of patients with argininosuccinate lyase (EC 4.3.2.1) deficiency (ASLD). Previous workers have reported the presence of anhydrides of ASA in the urine of patients with this disorder. We have used 1H-NMR spectroscopy to investigate the presence of these compounds in untreated urine. Our results indicate that the anhydrides were absent from urine and are artifacts produced by the conditions prevailing in the methods of analysis previously used to investigate the urine from patients with ASLD. We have also attempted to reproduce the conditions that might promote the transition to the anhydrides in the urine from a patient with ASLD and in solutions of argininosuccinate. Resolution of ASA and the two anhydrides is possible and a spectrum of the urine from a patient with ASLD shows that the anhydrides are present at below 1% of the total ASA under normal physiological conditions.
Amino Acid Metabolism, Inborn Errors↗
[The intermediate form of maple syrup disease].
A severely retarded and tetraspastic child died at the age of four years upon a respiratory infection with acidosis, disturbances of serum electrolytes and lactic aciduria. Brain autopsy showed a spongy degeneration and led to suspect an inborn error of amino-acid metabolism. These findings corresponded with the results of computer-tomography and were supported by post mortem amino-acid analysis. An intermediate variant of leucinosis was detected in an younger sister at the age of five months after cerebral convulsions and opisthotonic posture. The activity of the branched chain ketoacid decarboxylase in fibroblasts was reduced to 3-4% of normal. A protein restricted diet allowed a nearly normal cerebral development and improvement of computer-tomographic results. The similarity of clinical and biochemical data in both children indicate that a maple syrup urine disease was most likely the underlying disease in the older sister. Later performed electron-microscopical examinations of the older sister indicate that spongy degeneration of the central nervous system in leucinoisis is caused by a spongy myelinopathy, which is different from the alterations found in Canavan's disease, what could be pointed out for the first time.
Amino Acids, Branched-Chain↗
Urea cycle enzymopathies.
Explore the source record for details and available documents.
Acetyltransferases↗
Treatment of inborn errors of urea synthesis: activation of alternative pathways of waste nitrogen synthesis and excretion.
Children with inborn errors of urea synthesis accumulate ammonium and other nitrogenous precursors of urea, leading to episodic coma and a high mortality rate. We used alternative pathways for the excretion of waste nitrogen as substitutes for the defective ureagenic pathways in 26 infants. These pathways involve synthesis and excretion of hippurate after sodium benzoate administration, and of citrulline and argininosuccinate after arginine supplementation. The children were treated for seven to 62 months; 22 survived. The mean plasma level of ammonium ( +/- S.E.) was 36 +/- 2 mumol per liter, and that of benzoate was 1.5 +/- 1.0 mg per deciliter. Alternative pathways accounted for between 28 and 59 per cent of the total "effective" excretion of waste nitrogen. Nineteen infants had normal height, weight, and head circumference, and 13 had normal intellectual development. Activation of alternative pathways of waste nitrogen excretion can prolong survival and improve clinical outcome in children with inborn errors of urea synthesis.
Amino Acid Metabolism, Inborn Errors↗
Interallelic complementation in an inborn error of metabolism: genetic heterogeneity in argininosuccinate lyase deficiency.
We used complementation analysis as a probe for the detection of genetic heterogeneity within a single locus affected in a human disease, argininosuccinate lyase (L-argininosuccinate arginine-lyase, EC 4.3.2.1) deficiency. Fibroblasts cultured from 28 unrelated patients were fused in all possible pairwise combinations, and the argininosuccinate lyase activity in heterokaryons was assayed by measuring the incorporation of 14C from L-[ureido-14C]citrulline into acid-precipitable material. Partial complementation was observed in fusions involving 20 of the 28 strains, with the lyase activity increasing from 2- to 10-fold. Thirteen of the mutants were identified by the complementation analysis as being phenotypically unique. Of the 20 complementing strains, 3 were remarkable because they participated in all but 2 of the 32 positive complementation tests; 2 others constituted a unique subgroup that produced the highest increases in argininosuccinate lyase activity of all fusions. The 8 strains that did not complement any others consisted of two types: 3 mutants with the highest residual argininosuccinate lyase activity of all strains and 5 mutants with low residual activity. All of the mutants mapped to a single major complementation group. The data could be summarized as a circular complementation map with an attached linear tail, the mutants being distributed among 12 subgroups in a complex pattern. We conclude that all of these mutants are affected at a single locus, that extensive genetic heterogeneity is present in the mutant population, and that the affected locus in argininosuccinate lyase deficiency is likely to be the structural gene coding for that enzyme.
Alleles↗
LCGreen I-based real-time PCR assays for detecting common ASL and HMGCL variants.
Explore the source record for details and available documents.
Amino Acid Metabolism, Inborn Errors↗
Sodium benzoate and arginine: alternative pathway therapy in inborn errors of urea synthesis.
Explore the source record for details and available documents.
Adolescent↗
Ammonia metabolism in a family affected by hyperargininemia.
A French-Canadian family, with a 14-year old mentally retarded girl, was investigated for hyperargininemia. The girl showed a fasting plasma ammonia N concentration of 100 micrograms/dl (normal : 50.5 +/- 13 micrograms/dl), and a two-hour post protein load level of 183 micrograms/dl (normal : 51.6 +/- 17.6 micrograms/dl). Plasma urea N was lower than normal in the post-load sample. Arginine concentrations were 11 times normal in the plasma, 47 times normal in the urine and 4 times normal in erythrocytes. Measurement of erythrocyte arginase showed only 1% activity in the propositus, and 52-54% in the parents and a sibling as compared to controls. In heterozygous members of the family, the Km (arginine) was similar to controls. Column chromatography of serum amino acids in the propositus showed arginine to be 17.6 S.D. higher than the normal mean. A characteristic cystine-lysinuria pattern of urinary amino acids was also seen. Measurement of other urinary nitrogenous metabolites showed low urinary urea and excessive orotic aciduria. On "normal" food intake, the patient excreted 122 mg of orotic acid/24 h, as against 3.7 mg by the sibling and 3.9 mg by the mother. It is postulated that the level of ornithine in hepatocyte mitochondria is critical to the disposal of carbamyl phosphate. The lack of normal regeneration of ornithine by liver arginase, and an excessive urinary excretion may be responsible for its low mitochondrial concentration. This would cause diversion of unmetabolised carbamyl phosphate towards orotic acid synthesis or ammonia production.
Adolescent↗
[Urea cycle disorders].
Explore the source record for details and available documents.
Amino Acid Metabolism, Inborn Errors↗
Pilot study of gas chromatographic-mass spectrometric screening of newborn urine for inborn errors of metabolism after treatment with urease.
Gas chromatographic-mass spectrometric (GC-MS) techniques for urinary organic acid profiling have been applied to high-risk screening for a wide range of diseases, mainly for inborn errors of metabolism (IEM), rather than to low-risk screening or mass screening. Using a simplified procedure with urease-pretreatment and the GC-MS technique, which allows simultaneous determination of organic acids, amino acids, sugars and sugar acids, we performed a pilot study of the application of this procedure to neonatal urine screening for 22 IEM. Out of 16,246 newborns screened, 11 cases of metabolic disorders were chemically diagnosed: two each of methylmalonic aciduria and glyceroluria, four of cystinuria, and one each of Hartnup disease, citrullinemia and alpha-aminoadipic aciduria/alpha-ketoadipic aciduria. The incidence of IEM was thus one per 1477, which was higher than the one per 3000 obtained in the USA in a study targeting amino acids and acylcarnitines in newborn blood spots by tandem mass spectrometry. Also, 227 cases were found to have transient metabolic abnormalities: 108 cases with neonatal tyrosinuria, 99 cases with neonatal galactosuria, and 20 cases with other transient metabolic disorders. Two hundred and thirty-eight cases out of 16,246 neonates (approximately 1/68) were thus diagnosed using this procedure as having either persistent or transient metabolic abnormalities.
Gas Chromatography-Mass Spectrometry↗
[Vegetarian diet in glutaric aciduria type I].
Glutaric aciduria type I is an autosomal recessive metabolic disease (1 case/30,000) characterized by a progressive dystonic-diakinetic syndrome in children. Pathologic examination reveals striatal degeneration of the caudate and putamen nucleus and biochemical analysis shows glutaryl CoA dehydrogenase deficiency. Values of glutaric and -hydroxyglutaric acids in urine are usually increased. Currently, the disease is considered untreatable since there are usually irreversible lesions in the central nervous system at diagnosis. However, treatment can be provided to pre-symptomatic children and usually to the siblings of patients with this diagnosis. We present the case of a 23-month-old boy, with macrocephaly and minimal neurologic manifestations at diagnosis, which were attributed to his semivegetarian diet. A dietary regimen and vitamin supplementation halted and even improved symptomatic progression of the disease. We conclude that amino and organic acids in urine should be investigated in all children with progressive macrocephaly of unknown etiology to rule out glutaric aciduria type I.
Amino Acid Metabolism, Inborn Errors↗
[Pathological and biochemical studies on a neonatal case of argininosuccinic aciduria (author's transl)].
A newborn infant affected by argininosuccinic aciduria was treated with a hypoproteinaemic diet and survived up to the age of three months. Post mortem biochemical studies have confirmed the absence of argininosuccinase activity in kidney, liver and brain and a marked storage of argininosuccinic acid in the brain. The histological study of the central nervous system shows no Alzheimer type II cells; there is neither demyelination nor spongiosis. Such results are totally different from those recorded in untreated cases; they represent very likely the effects of the diet which has controlled the hyperammoniaemia and prevented a deficiency of arginine.
Amino Acid Metabolism, Inborn Errors↗
Demonstration of N-dicarboxyl-mono-glycines in dicarboxylic acidurias by mass fragmentography.
Urine samples from 18 individuals with various types of dicarboxylic acidurias have been investigated by mass fragmentography for N-dicarboxyl-mono-glycines (dicarboxylglycines). One patient with methylmalonic acidemia excreted 14-20 microgram methylmalonylglycine/mg creatinine, three patients with glutaric aciduria excreted 20-60 microgram glutarylglycine/creatinine, and one patient with C6-C10-dicarboxylic aciduria excreted 120-365 microgram succinylglycine/mg creatinine. Excretion of C6-C10-dicarboxylic acids in patients with ketosis and glycogenosis and in neonates were not accompanied by excretion of C8-C10-dicarboxylglycines in measurable amounts (greater than 1 microgram/mg creatinine). Nor did patients with succinic aciduria excrete succinylglycine in amounts larger than 1 microgram/mg creatinine. On the basis of these data it is argued that production of short- and medium-chain dicarboxylglycines is not a metabolic pathway of biological significance for the elimination of short- and medium-chain dicarboxylic acids from individuals with dicarboxylic acidurias.
Adolescent↗
Neuroradiologic findings in glutaric aciduria type II.
The authors report a 3-year-old male with glutaric aciduria type II, whose magnetic resonance imaging studies revealed agenesis of the cerebellar vermis and hypoplastic temporal lobes. Proton magnetic resonance spectroscopy in the parietal white matter revealed a markedly increased choline/creatine ratio, suggesting a demyelinating process. Gas chromatographic analysis of urinary organic acids should be studied in any patient with agenesis of the cerebellar vermis and cystic renal disease to exclude glutaric aciduria type II.
Amino Acid Metabolism, Inborn Errors↗