1/43. Defect in dimethylglycine dehydrogenase, a new inborn error of metabolism: NMR spectroscopy study.BACKGROUND: A38-year-old man presented with a history of fish odor (since age 5) and unusual muscle fatigue with increased serum creatine kinase. Our aim was to identify the metabolic error in this new condition. methods: We used 1H NMR spectroscopy to study serum and urine from the patient. RESULTS: The concentration of N, N-dimethylglycine (DMG) was increased approximately 100-fold in the serum and approximately 20-fold in the urine. The presence of DMG as a storage product was confirmed by use of 13C NMR spectroscopy and gas chromatography-mass spectrometry. The high concentration of DMG was caused by a deficiency of the enzyme dimethylglycine dehydrogenase (DMGDH). A homozygous missense mutation was found in the DMGDH gene of the patient. CONCLUSIONS: DMGDH deficiency must be added to the differential diagnosis of patients complaining of a fish odor. This deficiency is the first inborn error of metabolism discovered by use of in vitro 1H NMR spectroscopy of body fluids.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
2/43. Enantioselective analysis of ketone bodies in patients with beta-ketothiolase deficiency, medium-chain acyl coenzyme a dehydrogenase deficiency and ketonemic vomiting.Enantioselective multidimensional gas chromatography-mass spectrometry (enantio-MDGC-MS) is a valuable tool for the differentiation of enantiomers from complex matrices when present in trace amounts. The separation of chiral compounds provides further information on the diagnosis of diseases, and on normal and abnormal biochemical pathways. The formation of the normal urinary metabolite 3-hydroxy-2-methylbutanoic acid (HMBA), excreted in abnormally high amounts in beta-ketothiolase deficiency, is not absolutely clarified. Metabolic pathways involving this metabolite are isoleucine catabolism, as well as presumably beta-oxidation of fatty acids and ketogenesis. The latter two pathways are distinguishable in their enantioselectivity. Enantioselective analysis gives further information on interfering metabolic pathways and the selectivity of the enzyme(s) forming HMBA. Different ratios of the stereoisomers of HMBA in control urine samples and patients with beta-ketothiolase deficiency were detected. Analogous to HMBA urinary 3-hydroxybutanoic acid (HBA) was investigated in several diseases. The formation of HBA and HMBA is expected to result from the same or similar metabolic pathways. Differences in the enantiomeric ratio of HMBA may originate from the enantioselectivity of different enzyme systems.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
3/43. Glutaric aciduria type II: observations in seven patients with neonatal- and late-onset disease.The clinical, biochemical, and neuroradiologic findings and clinical follow-up of seven patients with glutaric aciduria type II are reported. Three phenotypes of the disease are encountered: neonatal-onset form with congenital anomalies (two patients) or without congenital anomalies (three patients) and late-onset form (two patients). The neonatal-onset form presents as an overwhelming illness, with severe hypoglycemia and metabolic acidosis leading to rapid death. Frequently it is associated with perinatal energy deprivation, a neonate with low birth weight and prematurity. The late-onset form presents with intermittent episodes of vomiting, hypoglycemia, and acidosis especially after meals rich in fat and/or proteins. All parents are consanguineous and have a first- or second-degree relationship. Initially, in the two phenotypes with neonatal onset and during crisis in the late-onset phenotype, routine laboratory evaluation showed severe metabolic acidosis, with an increased anion gap, hypoglycemia without ketonuria, and disturbed liver function tests. In the majority of patients with neonatal-onset forms, the kidneys, liver, and at times the spleen are enlarged with an increased echogenic pattern; however, no hepatic or renal cysts are detected. cardiomegaly is observed in most patients. The diagnosis can be easily and rapidly reached through tandem mass spectrometry study of the blood and can further be confirmed by gas chromatography/mass spectrometry analysis of the urine organic acids. In this report, the magnetic resonance imaging/computed tomography brain studies showed brain atrophy, white matter disease, and in one patient, fluid-filled cavities in the periventricular area and putamina. fluorine-18-labeled 2-fluoro-2-deoxyglucose positron emission tomographic (FDG PET) brain studies in two patients with late-onset disease showed slightly decreased activity in the cerebral cortex in one and in the caudate nuclei in the other. brain FDG PET scan and magnetic resonance spectroscopy were normal in one patient with neonatal-onset disease. All patients were treated with a diet low in fat and protein, oral riboflavin, and carnitine. The results were promising for the late-onset disease. Intravenous carnitine gave rewarding results in one patient with neonatal-onset disease.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
4/43. Children with bilateral temporal arachnoid cysts may have glutaric aciduria type 1 (GAT1); operation without knowing that may be harmful.BACKGROUND: Bilateral, temporal arachnoid cysts are common in patients with Glutaric aciduria type 1 (GAT1). The present study investigates whether bitemporal cysts may occur unrelated to GAT1. and it reports our experience with 2 GAT1 patients. methods: During the last 11 years, the regional neurosurgical department has seen a total of 147 patients with arachnoid cysts in a population of 890,000. Eight of these patients had bitemporal arachnoid cysts, 4 boys, 3 adult females, and 1 adult male. urine from 7 of these patients was examined with gas chromatography-mass spectrometry. FINDINGS: Large amounts of glutaric acid were discovered in the urine of only 2 of these patients, both young boys with severe neurological symptoms of the disease. One of them died 2 years after the clinical start of the disease. The remaining 5 urinary specimens contained low (normal) concentrations of glutaric acid. INTERPRETATION: For neurosurgeons, it is important to recognise that children with bitemporal arachnoid cysts may have GAT1, and that even simple surgical procedures may be extremely harmful for such patients. All paediatric patients with bitemporal arachnoid cysts should therefore be screened for GAT1 before any surgical procedure takes place, especially if there is also macrocephaly, an acute encephalitis-like illness, or a dystonic, cerebral palsy-like condition. It is concluded that bitemporal arachnoid cysts are extremely rare, and that they may well occur unrelated to GAT1.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
5/43. Establishing gas chromatography-mass spectrometry to diagnose organic acidemias in thailand.Disorders of organic acid metabolism are a group of disorders which has long been ignored by majority of Thai physicians. Part of this is due to lack of laboratories in thailand to verify the diagnosis of the disorders. We have recently developed a technique to qualitatively analyze organic acids utilizing gas chromatography-mass spectrometry (GC-MS). Eight patients in four families were successfully identified as having organic acidemias (OA) by this method. Two families had methylmalonic acidemia, one had propionic acidemia, and the other had 3-methylcrotonyl CoA carboxylase deficiency. To our knowledge, this is the first laboratory in thailand being able to use GC-MS to diagnose OA. Availability of a laboratory in thailand and affordability of the test are expected to result in earlier diagnosis and identification of more cases of OA in Southeast Asian countries. Consequently, prompt and proper treatment can be anticipated which should lead to better prognosis for patients with this group of disorder.- - - - - - - - - - ranking = 4keywords = chromatography (Clic here for more details about this article) |
6/43. Detection of inborn errors of metabolism in Thai infants via gas chromatography and mass spectrometry.We had studied inherited metabolic disorders at the Department of pediatrics, Siriraj Hospital faculty of medicine, Mahidol University since 1987 using limited resources available and collaboration with other laboratories, both in thailand and The united states. Since April 1998, we started a collaboration with MILS and Kanazawa Medical University, the japan, studying inborn errors of metabolism in Asian Countries using urine filter paper and a new GC/MS method. We have since successfully discovered several patients with metabolic disorders. Out of 33 (high-risk) cases we sent for biochemical diagnosis (during April-July 1998), 13 abnormal results were found which is approximately 39.4%. Inherited metabolic disorders identified were as follows: medium-chain acyl CoA dehydrogenase deficiency (MCAD), multiple carboxylase deficiency (MCD), methylmalonic acidemia (MMA), fanconi syndrome, galactosemia and neuroblastoma.- - - - - - - - - - ranking = 4keywords = chromatography (Clic here for more details about this article) |
7/43. apolipoprotein a-i deficiency with accumulated risk for CHD but no symptoms of CHD.We evaluated a 69-year-old Japanese woman with apolipoprotein (apo) A-I deficiency, high levels of low-density lipoprotein (LDL)-cholesterol, hypertension and impaired glucose tolerance. The patient had corneal opacity, but neither xanthomas, xanthelasma, nor tonsillar hypertrophy. She was not symptomatic for coronary heart disease (CHD), and had normal electrocardiograms at rest and exercise using a cycle ergometer. She had severely reduced levels of high-density lipoprotein (HDL)-cholesterol (0.10-0.18 mmol/l) and no apo A-I (<0.6 mg/dl). LDL-cholesterol and apo B as well as apo E were increased even under treatment with 10 mg pravastatin per day. Gel filtration chromatography revealed that in addition to VLDL and LDL fractions, she had apo A-II rich and apo E rich fractions, which were present in the HDL fraction separated by ultracentrifugation. A cytosine deletion was identified by genomic dna sequencing of the apo A-I gene of the patient at the third base of codon 184 in the fourth exon, which led to a frame shift mutation and early termination at codon 200. This patient is the oldest among those with apo A-I deficiency reported in the literature, and she had no symptoms of CHD despite the accumulated risk for the disease.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
8/43. Two cases of benign methylmalonic aciduria detected during a pilot study of neonatal urine screening.Two cases of benign methylmalonic aciduria (MMAuria) were found among 9780 neonatal screenings using the previously described screening method consisting of urease digestion, ethanol deproteinization and gas chromatography-mass spectrometry. Combining this screening method with the stable isotope dilution technique showed very specific and sensitive measurements of methylmalonic acid in urine. The concentrations of urinary methylmalonic acid were measured at several ages. The levels of urinary methylmalonic acid in two patients varied from 0.27 to 3.04 mol/mol creatinine (control<0.01 mol/mol creatinine). Methylcitrate and homocystine were not increased in the patient's urine or blood. blood propionylcarnitine was also at normal levels. The urinary methylmalonate excretions were decreased to the levels of about 50% of the start point after vitamin B12 treatment in one patient, but the other patient showed no change. No clinical abnormalities were observed during these periods.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
9/43. Effect of valproic acid on the urinary metabolic profile of a patient with succinic semialdehyde dehydrogenase deficiency.The metabolic changes in a patient with succinic semialdehyde dehydrogenase deficiency were investigated following valproate administration using urease pretreatment and gas chromatography-mass spectrometry. A stable isotope dilution technique was used for quantification of urinary 4-hydroxybutyrate. Urinary levels of 4-hydroxybutyrate were 4-fold higher after 1-month valproate therapy. 4,5-Dihydrohexanoate, 2-deoxytetronate and 3-deoxytetronate were also 1.7-2.7-fold higher. The urinary excretions of 4-hydroxybutyrate in valproate non-medicated controls were age dependence and decreased with age. Relationships between 4-hydroxybutyrate excretion and 4-hydroxyvalproate or 5-hydroxyvalproate excretion were observed in valproate medicated controls. It seems that 4-hydroxyvalproate and 5-hydroxyvalproate as well as valproate are involved with increased excretion of 4-hydroxybutyrate following valproate administrations.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
10/43. Biochemical diagnosis and outcome of 2 years treatment in a patient with combined methylmalonic aciduria and homocystinuria.We describe a patient with methylmalonic aciduria and homocystinuria due to a defect in cobalamin metabolism of the Cbl-C type mutant (McKusick 277400). Our case was diagnosed within the first 2 months of life by amino acid analysis (ion-exchange chromatography) and by biochemical studies in cultured fibroblasts ([14C]propionate incorporation, methionine and serine formation). We discuss the clinical course and the biochemical evolution after 2 years of hydroxycobalamin treatment that led to an improvement in general clinical condition and neurological performance.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
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