Search PubMed⌕ Search

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.

At least 811 records · Page 45Linked to original sources

Ca(2+) and Na(+) dependence of 3-hydroxyglutarate-induced excitotoxicity in primary neuronal cultures from chick embryo telencephalons.

Glutaryl-CoA dehydrogenase deficiency (also known as glutaric aciduria type I) is an autosomal, recessively inherited neurometabolic disorder with a distinct neuropathology characterized by acute encephalopathy during a vulnerable period of brain development. Neuronal damage in this disease was demonstrated to involve N-methyl-D-aspartate (NMDA) receptor-mediated neurotoxicity of the endogenously accumulating metabolite 3-hydroxyglutarate (3-OH-GA). However, it remained unclear whether NMDA receptors are directly or indirectly activated and whether 3-OH-GA disturbs the intracellular Ca(2+) homeostasis. Here we report that 3-OH-GA activated recombinant NMDA receptors (e.g. NR1/NR2A) but not recombinant alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (e.g. GluR-A/GluR-B) in HEK293 cells. Fluorescence microscopy using fura-2 as Ca(2+) indicator revealed that 3-OH-GA increased intracellular Ca(2+) concentrations in the presence of extracellular Ca(2+) in cultured chick neurons. Similar to glutamate-induced cell damage, 3-OH-GA neurotoxicity was modulated by extracellular Na(+). The large cation N-methyl-D-glucamine, which does not permeate NMDA receptor channels, enhanced 3-OH-GA-induced Ca(2+) increase and cell damage. In contrast, 3-OH-GA-induced neurotoxicity was reduced after replacement of Na(+) by Li(+), which permeates NMDA channels but does not affect the Na(+)/Ca(2+) exchanger in the plasma membrane. Spectrophotometric analysis of respiratory chain complexes I-V in submitochondrial particles from bovine heart revealed only a weak inhibition of 3-OH-GA on complex V at the highest concentration tested (10 mM). In conclusion, the present study revealed that NMDA receptor activation and subsequent disturbance of Ca(2+) homeostasis contribute to 3-OH-GA-induced cell damage.

Adenosine Triphosphatases↗

First trimester diagnosis of methylmalonic aciduria.

We have studied methylmalonyl CoA mutase activity in control chorionic villi to establish the potential use of assays performed directly on this tissue for prenatal diagnosis of methylmalonic aciduria. We report the detection of a fetus affected with the apo-mutase deficient form of this condition at 9 weeks' gestation. Methylmalonyl CoA mutase was markedly deficient in chorionic villi, approximately 2.5 per cent of the mean control value. However, incorporation of label from [14C]-propionate into protein was 10 and 40 per cent of the mean control value, respectively, in two portions of the same biopsy, highlighting potential problems in the use of this indirect assay. Normal results were obtained in chorionic villus samples from four other pregnancies 'at risk' for methylmalonic aciduria which were subsequently shown to be unaffected with this condition. The diagnosis in the affected pregnancy was confirmed by demonstration of a marked deficiency of methylmalonyl CoA mutase activity in villi obtained at termination and in cultured fetal fibroblasts. Reduced incorporation of [14C]-propionate label into protein was also found in these tissues.

Amino Acid Metabolism, Inborn Errors↗

A biochemical investigation of auranofin nephrotoxicity by high field proton nuclear magnetic resonance (NMR) spectroscopy.

High-field proton NMR spectroscopic analysis of urine and plasma has been employed to study the biochemical effects and nephrotoxic action of an intramuscular dose of auranofin in rats. Auranofin induced a characteristic profile of proximal tubular damage as evidenced by aminoaciduria, lactic aciduria and increased urinary acetate concentrations. In addition, ethanol was detectable in both urine and plasma obtained from auranofin-treated rats. Auranofin-mediated elevations in the plasma and urine concentrations of 3-D-hydroxybutyrate indicated an increased utilisation of fats for fuel in rats treated with this novel therapeutic agent.

Acetates↗

Molecular basis of 3-hydroxy-3-methylglutaric aciduria.

3-Hydroxy-3-methylglutaric aciduria is a human autosomal recessive metabolic disorder that usually appears within the first year of life. The causes of this aciduria are lethal mutations in the gene encoding for 3-hydroxy-3-methylglutaryl coenzyme A lyase (HL). HL is a mitochondrial matrix enzyme that catalyzes the last step of ketogenesis and leucine catabolism. This gene has been mapped to chromosome 1 at locus 1pter-p33 and its genomic organisation comprises 9 exons whose sizes vary between 64-678 bp. The human cDNA sequence was reported in 1993 with the first genetic study of two Acadian-French Canadian siblings. To date, 24 mutations in 36 patients have been described; most of them are single-base substitutions causing amino acid replacements and a variety of splicing defects. In the population studied two mutations appear predominant: g.122GA (8 patients and 15 alleles) frequent in Saudi Arabia, and g.109GT (6 patients and 12 alleles), prevalent in Spain. At least seven mutations are clustered in the second half of exon 2 affecting aminoacids E37, R41 and D42 and conforming a possible hot spot. The genotype-phenotype correlation is difficult to establish since the probands received different treatments, and the onset of an acute episode frequently depends on external factors such as fasting or acute illness.

Alternative Splicing↗

Identification of the gene responsible for the cblB complementation group of vitamin B12-dependent methylmalonic aciduria.

The methylmalonic acidurias are metabolic disorders resulting from deficient methylmalonyl-CoA mutase activity, a vitamin B(12)-dependent enzyme. We have cloned the gene for the cblB complementation group caused by deficient activity of a cob(I)alamin adenosyltransferase. This was accomplished by searching bacterial genomes for genes in close proximity to the methylmalonyl-CoA mutase gene that might encode a protein with the properties of an adenosyltransferase. A candidate was identified in the Archaeoglobus fulgidus genome and was used to probe the human genome database. It yielded a gene on chromosome 12q24 that encodes a predicted protein of 250 amino acids with 45% similarity to PduO in Salmonella enterica, a characterized cob(I)alamin adenosyltransferase. A northern blot revealed an RNA species of 1.1 kb predominating in liver and skeletal muscle. The gene was evaluated for deleterious mutations in cblB patient cell lines. Several mutations were identified including a 5 bp deletion (5del572gggcc576), two splice site mutations (IVS2-1G>T, IVS3-1G>A), andt several point mutations (A135T, R186W, R191W and E193K). Two additional amino acid substitutions (R19Q and M239K) were found in several patient cell lines but were found to be common polymorphisms (36% and 46%) in control alleles. The R186W mutation, which we suggest is disease-linked, is present in four of the six patient cell lines examined (homoallelic in two) and in 4 of 240 alleles in control samples. These data confirm that the identified gene, MMAB, corresponds to the cblB complementation group and has the appearance of a cob(I)alamin adenosyltransferase, as predicted from biochemical data.

Alkyl and Aryl Transferases↗

Hydroxypyruvate-mediated regulation of oxalate synthesis by lactate dehydrogenase and its relevance to primary hyperoxaluria type II.

Hydroxypyruvate (HP) brought about the decarboxylation of [1-14C] glyoxylate nonenzymically at all pH values considered. The rate of decomposition of glyoxylate increased with each increase in the concentrations of the reactants, the pH, and temperature and on the addition of the cations Fe2+, Mn2+, Mg2+, Zn2+, Co2+, and Cu2+. The addition of HP to a purified preparation of lactate dehydrogenase (LDH) catalyzing the oxidation of [1-14C]glyoxylate to [14C]oxalate in the presence of either NAD or NADH inhibited the production of oxalate. These observations have their implications in L-glyceric aciduria (primary hyperoxaluria type II), a syndrome characterized by the accumulation of HP and recurrent oxalosis. They suggest that the accumulating HP may reduce the contribution of intracellular glyoxylate to the formation of oxalate by competitively inhibiting the liver LDH. The involvement of liver LDH in oxalate synthesis and its postulated induction by HP and NAD in vivo are, therefore, reexamined.

Amino Acid Metabolism, Inborn Errors↗

Erythrocyte formimino glutamate transferase in FIGLU aciduria.

A patient is described who presented at an early age with failure to thrive and vomiting, and had a gross excretion of formimino glutamic acid. She had normal concentration of serum folate and vitamin B12, and no haematological abnormalities, and is not mentally retarded. The Michaelis constant for erythrocyte formimino glutamate transferase was in the normal range, but the enzyme behaves differently from that from reference subjects with respect to inhibitors and activators.

Amino Acid Metabolism, Inborn Errors↗

A gene encoding a putative FAD-dependent L-2-hydroxyglutarate dehydrogenase is mutated in L-2-hydroxyglutaric aciduria.

The purpose of this study was to identify the biochemical and genetic defect in L-2-hydroxyglutaric aciduria, a neurometabolic disorder characterized by the presence of elevated concentrations of L-2-hydroxyglutaric acid in urine, plasma, and cerebrospinal fluid. Evidence is provided for the existence in rat tissues of a FAD-dependent enzyme catalyzing specifically the oxidation of L-2-hydroxyglutarate to alpha-ketoglutarate. This enzyme is mainly expressed in liver and kidney but also at lower levels in heart, brain, and other tissues. Subcellular fractionation indicates that the liver enzyme is present in mitochondria, where it is bound to membranes. Based on this information, a database search led to the identification of a gene encoding a human hypothetical protein homologous to bacterial FAD-dependent malate dehydrogenases and targeted to mitochondria. The gene encoding this protein, present on chromosome 14q22.1, was found to be in a region homozygous in patients with L-2-hydroxyglutaric aciduria from two consanguineous families. Three mutations that replaced a highly conserved residue (Lys-71-Glu and Glu-176-Asp) or removed exon 9 were identified in homozygous state in patients from three distinct families and were found to cosegregate with the disease. It is concluded that L-2-hydroxyglutarate is normally metabolized to alpha-ketoglutarate in mammalian tissues and that L-2-hydroxyglutaric aciduria is caused by mutations in the gene that most likely encodes L-2-hydroxyglutarate dehydrogenase. The pathological findings observed in this metabolic disorder must therefore be due to a toxic effect of L-2-hydroxyglutarate on the central nervous system.

Alcohol Oxidoreductases↗

Frequencies of inherited organic acidurias and disorders of mitochondrial fatty acid transport and oxidation in Germany.

UNLABELLED: The lack of epidemiological data on the frequency and/or burden of organic acidurias (OA) and mitochondrial fatty acid transport and oxidation disorders (mtFATOD) is one reason for hesitation to expand newborn screening (NBS) by tandem mass spectrometry (MS-MS). From 1999 to 2000, the frequency of ten potentially treatable OA and mtFATOD was assessed by active nation-wide surveillance on cases presenting with clinical symptoms using the German Paediatric Surveillance Unit (ESPED) system. Case ascertainment was complemented by a second independent source: 3-monthly inquiries in the metabolic laboratories performing secondary selected screening for OA and mtFATOD. Frequency estimates for clinically symptomatic cases older than 7 days in a birth cohort of 844,575 conventionally screened children was compared to the frequency found in a cohort of 382,247 screened by MS-MS in Bavaria and Baden-Württemberg. The overall frequency of the ten conditions considered was 1:8,000 (95% CI 1:11,000-1:6,000) by MS-MS as compared to 1:23,000 (95% CI 1:36,000-1:17,000) in symptomatic cases presenting mainly with metabolic crisis. The contributions of medium-chain acyl-CoA dehydrogenase deficiency (MCADD), other mtFATOD and OA were 29, 4 and 13 among the 46 cases identified by MS-MS, and 19, 1 and 13 among the 33 clinically symptomatic cases, respectively. Acute metabolic crisis, with a lethal outcome in four patients, was reported for 22/33 clinically symptomatic cases. No clinically symptomatic cases were reported from cohorts with screened by MS-MS. CONCLUSION: ten potentially treatable organic acidurias and mitochondrial fatty acid transport and oxidations disorders were more common than phenylketonuria with organic acidurias accounting for 28% of the cases detected by newborn screening and 39% of the cases identified on high risk screening. These conditions were related to considerable morbidity and mortality. Considerations for their inclusion in expanded newborn screening programmes might be warranted.

Acyl-CoA Dehydrogenase↗

Correction of ornithine transcarbamylase deficiency in adult spf(ash) mice and in OTC-deficient human hepatocytes with recombinant adenoviruses bearing the CAG promoter.

Ornithine transcarbamylase (OTC) deficiency, the most common and severe inborn error of the urea cycle in humans, remains without adequate treatment, and mortality rates are high. Adenoviral vectors provide an efficient system for gene delivery, but there are problems, including toxicity. Efficient promoters that reduce the amount of vector required for treatment need to be developed. We constructed two recombinant adenoviral vectors, AdexCAGhOTC and AdexSR alpha hOTC, which harbor the human OTC gene under transcriptional control of CAG (a modified chicken beta-actin promoter with CMV-IE enhancer) and SR alpha (the SV40 early promoter with the R segment and part of the US segment of the HTLV-1 LTR), respectively. Each was tested in adult spf(ash) mice, an animal model of human OTC deficiency, and in primary human hepatocytes with OTC deficiency. Spf(ash) mice have a pronounced orotic aciduria as seen in humans. A complete recovery of hepatic OTC activity with minimal tissue damage was observed in these animals following the intravenous administration of AdexCAGhOTC alone. Western blot analysis confirmed hepatic OTC expression and normalization of orotic aciduria was evident for 60 days. Enzyme activities of primary human hepatocytes infected with AdexCAGhOTC were 10-40 times higher than those with AdexSR alpha hOTC. Thus, the adenoviral vector with an efficient promoter such as CAG, can be given further consideration for possible gene therapy in humans with OTC deficiency.

Actins↗

Methylcitric acid determination in amniotic fluid by electron-impact mass fragmentography.

Methylcitric acid, a metabolite of abnormal propionyl-CoA metabolism, is elevated in amniotic fluid when the fetus is affected with propionic acidaemia or methylmalonic aciduria. We developed a method for quantifying methylcitric acid in amniotic fluid by solid-phase extraction, derivatisation to the t-butyl-dimethylsilylester, and gas chromatography-mass spectrometry with electron-impact ionisation, using the deuterated analogue of methylcitric acid as an internal standard. The main advantages are a good sensitivity, simple sample preparation, and feasibility on instruments equipped with mass specific detectors.

Amino Acid Metabolism, Inborn Errors↗

Ornithine transcarbamylase deficiency in females: an often overlooked cause of treatable encephalopathy.

Ornithine transcarbamylase deficiency is an X-linked recessive disorder of urea biosynthesis characterized by recurrent, often fatal, hyperammonemic encephalopathy in affected males; carrier females are usually asymptomatic. We report here the clinical and laboratory findings in five symptomatic heterozygous females with ornithine transcarbamylase deficiency. In each case, the onset of symptoms occurred in the 1st year of life, but diagnosis was delayed by up to 15 years. Symptoms included recurrent vomiting with lethargy (five patients), dietary protein intolerance (five), irritability (four), severe acute encephalopathy (three), ataxia (three), and acute hemiparesis (two). All eventually showed evidence of developmental delay or learning difficulties. Two of the three who experienced severe, acute, hyperammonemic encephalopathy suffered serious, permanent neurologic sequelae. Three of the patients showed decreased ornithine transcarbamylase activity in liver obtained by needle biopsy, and the other two had marked orotic aciduria associated with hyperammonemia. Neuroimaging studies demonstrated persistent abnormal lobar attenuation and abnormal signal on computed tomographic scan and magnetic resonance imaging. All patients showed marked symptomatic improvement on treatment with dietary protein restriction supplemented by pharmacologic measures to increase nonprotein nitrogen excretion. Ornithine transcarbamylase deficiency should be considered in the differential diagnosis of acute or chronic encephalopathy in females at any age.

Adolescent↗

A case of formiminoglutamic aciduria. Clinical and biochemical studies.

We describe a boy who excreted massive amounts of formiminoglutamic acid and hydantoin-5-propionic acid in his urine. He was mildly mentally retarded and epileptic, whereas his twin-brother was completely normal. Loading with L-histidine enhanced the excretion of both metabolites. Treatment was attempted with high doses of folic acid and methionine, but both were without effect on the excretion levels.

Amino Acid Metabolism, Inborn Errors↗

Differential diagnosis of mut and cbl methylmalonic aciduria by DNA-mediated gene transfer in primary fibroblasts.

Methylmalonic aciduria can be caused by mutations in the gene encoding the methylmalonyl coenzyme A mutase apoenzyme (mut) or genes required for the provision of cofactor B12 (cbl). The mut and cbl forms are classically differentiated by somatic cell complementation. We describe a novel method for differential diagnosis of mut and cbl methylmalonic aciduria using DNA-mediated gene transfer of a methylmalonyl CoA mutase cDNA clone. Gene transfer of a functional methylmalonyl CoA mutase cDNA clone into mut fibroblasts reconstitutes holoenzyme activity measured by metabolism of [14C]-propionate in culture. Identical gene transfers into cbl fibroblasts have no effect. This method is used for the differential diagnosis of mut and cbl genotypes in cells from patients with a clinical diagnosis of methylmalonic aciduria and is shown to be a facile, sensitive, and specific method for genetic diagnosis. This work establishes the principle of using DNA-mediated gene transfer to identify the genotype of diseases which can result from mutations at several different genetic loci. This type of differential genotypic diagnosis will be particularly important for establishing the applicability of somatic gene therapy in individual patients.

Amino Acid Metabolism, Inborn Errors↗

Novel mutations of the glutaryl-CoA dehydrogenase gene in two Japanese patients with glutaric aciduria type I.

We identified three different point mutations in the glutaryl-CoA dehydrogenase (GCDH) gene in two unrelated Japanese patients with glutaric aciduria type I (GA-I). One patient was a homozygote for Arg355His and the other a compound heterozygote for Ser305Leu and Met339Val. Arg355His and Met339Val are mutations hitherto undescribed, and all three mutations are predicted to alter the secondary structure of GCDH. Molecular analysis is useful for definite diagnosis and/or prenatal diagnosis of GA-I.

Amino Acid Metabolism, Inborn Errors↗

Purification, characterization, and localization of aspartoacylase from bovine brain.

Canavan disease, an autosomal recessive disorder, is characterized biochemically by N-acetylaspartic aciduria and aspartoacylase (N-acyl-L-aspartate amidohydrolase; EC 3.5.1.15) deficiency. However, the role of aspartoacylase and N-acetylaspartic acid in brain metabolism is unknown. Aspartoacylase has been purified to apparent homogeneity with a specific activity of approximately 19,000-20,000 nmol of aspartate released/mg of protein. The native enzyme is a 58-kDa monomer. The purified aspartoacylase activity is enhanced by divalent cations, nonionic detergents, and dithiothreitol. Low levels of dithiothreitol or beta-mercaptoethanol are required for enzyme stability. Aspartoacylase has a Km of 8.5 x 10(-4) M and a Vmax of 43,000 nmol/min/mg of protein. Inhibition of aspartoacylase by glycyl-L-aspartate and amino derivatives of D-aspartic acid suggests that the carbon backbone of the substrate is primarily involved in its interaction with the active site and that a blocked amino group is essential for the catalytic activity of aspartoacylase. Biochemical and immunocytochemical studies revealed that aspartoacylase is localized to white matter, whereas the N-acetylaspartic acid concentration is threefold higher in gray matter than in white matter. Our studies so far indicate that aspartoacylase is conserved across species during evolution and suggest a significant role for aspartoacylase and N-acetylaspartic acid in normal brain biology.

Amidohydrolases↗

Screening for metabolic disease in a metropolitan hospital.

Screening for metabolic diseases at Children's Hospital of Michigan, Detroit during 1978 and 1979 led to the discovery of 7.5 cases per year, representing a marked increase over previous years. Five cases of organic aciduria were identified during this two-year period by use of urinary gas chromatography. Four of these were found to have methylmalonic aciduria. The increase in detection rate was due to the addition of an organic acid screening technique and greater use of two standard screening tests. The yield of screening by these two tests also improved, which we attribute to the better use of specific criteria. Inclusion of a simple urine screening test for methylmalonic acid is recommended in the workup of infants with episodic vomiting, lethargy, acidosis, or catastrophic illness.

Amino Acid Metabolism, Inborn Errors↗

Mutation analysis of the GCDH gene in Italian and Portuguese patients with glutaric aciduria type I.

Two novel (G390V and X439W) and five already known mutations were identified in a total of 14 GA I alleles from Italy and Portugal. The substitution X439W is a rare type of mutation, which breaks the stop codon of the GCDH gene. As described in other populations, R402W was the most common mutation. Genotype R227P/R402W was found in a patient with low glutarate excretion. Haplotype studies have also been performed.

Amino Acid Substitution↗