Prenatal exclusion of ornithine transcarbamylase (OTC) by using RFLP analysis.
Explore the source record for details and available documents.
Blotting, Southern↗
Biomedical subjects
C Bachmann
Publications and source records attributed to C Bachmann.
Early diagnosis and treatment of neonatal medium-chain acyl-CoA dehydrogenase deficiency: report of two siblings.
Two siblings are reported who were symptomatic in the neonatal period. The first died suddenly at 4 days of age after regurgitating a meal. The postmortem examination showed steatosis of the liver, kidney and muscle. In the second, medium-chain acyl-CoA dehydrogenase (MCAD) deficiency was diagnosed at 3 days of age with muscular hypotonia, vomiting, hyperammonaemia and mild acidosis. Thus disorders of fatty acid oxidation should also be considered in newborns. The biochemical work up indicates that in neonates, analysis of serum medium-chain fatty acids and of acyl and free carnitine are more likely to lead to a diagnosis than determining dicarboxylic acids alone in urine. Long-term treatment was effective and monitored by the acyl/free carnitine ratio.
Acid-Base Equilibrium↗
Late-onset form of partial N-acetylglutamate synthetase deficiency.
A 13-month-old female presented with neurological deterioration of 1 month duration and hyperammonaemia. N-acetylglutamate synthetase activity in the liver was reduced to 33% of the control. A male cousin and a female sister had died following a similar clinical course. This is the first report of late-onset N-acetylglutamate synthetase deficiency. An autosomal-recessive mode of inheritance is suggested.
Acetyltransferases↗
Antibiotic therapy for improvement of metabolic control in methylmalonic aciduria.
Explore the source record for details and available documents.
Amino Acid Metabolism, Inborn Errors↗
Guanidino compound analysis as a complementary diagnostic parameter for hyperargininemia: follow-up of guanidino compound levels during therapy.
The aim of this collaborative study was to investigate whether guanidino compound analyses in the biologic fluids can be used as a complementary diagnostic parameter for hyperargininemia. Guanidino compounds were determined in the biologic fluids of all known living hyperargininemic patients using a cation exchange chromatographic system with a fluorescence detection method. The serum arginine, homoarginine, alpha-keto-delta-guanidino-valeric acid, argininic acid, and N-alpha-acetylarginine levels of all the hyperargininemic patients are higher than the normal range. Similar increases were seen for the urinary excretion of alpha-keto-delta-guanidinovaleric acid and argininic acid. Untreated hyperargininemic patients have the highest guanidino compound levels in cerebrospinal fluid. However, even under therapy, the arginine, homoarginine, alpha-keto-delta-guanidinovaleric acid, and argininic acid levels in cerebrospinal fluid are still increased. Protein restriction alone is not sufficient to normalize the hyperargininemia, but protein restriction together with supplementation of essential amino acids with or without sodium benzoate decreases further the arginine levels. However, whereas the argininemia can be normalized, the catabolites of arginine are still increased. We conclude that the urinary amino acid levels may remain normal in hyperargininemia, whereas consistent increases of the guanidino compounds are observed. Thus, guanidino compound analyses can be used as a complementary biochemical diagnostic parameter for hyperargininemia. Although the argininemia can be normalized by therapy, the levels of the catabolites of arginine are still elevated.
Adolescent↗
Proton NMR observation of phenylalanine and an aromatic metabolite in the rabbit brain in vivo.
1H nuclear magnetic resonance (NMR) was used to detect directly the signal from the aromatic protons of phenylalanine (phe) in the brains of rabbits made hyperphenylalaninemic by administration of a diet high in phe and containing 0.4% alpha-methylphenylalanine. In addition to those resonances found in the region between 6.5 and 8.5 ppm in the 1H NMR spectra of control rabbits, a resonance centered at 7.37 ppm was observed in the spectra obtained from the brains of hyperphenylalaninemic rabbits in vivo or in situ postmortem. The chemical shift of this additional resonance was that expected for protons of the phenyl ring of phe. Its intensity correlated well with measurements of brain phe levels made on postmortem samples by amino acid analyzer. Both of these measurements correlated poorly with amino acid analyzer measurements of serum phe, especially at high values of the latter. High-resolution 1H NMR spectra of the brain extracts showed that in most animals an unidentified aromatic compound, possibly gamma-glutamyl-phe, was present in addition to phe. This study demonstrates the feasibility of measuring the concentration of brain phenyl and its metabolites noninvasively by 1H NMR. The method can be used for similar measurements in human brain.
Animals↗
Exercise-induced hyperammonemia in patients with compensated chronic liver disease.
Plasma levels of ammonia and amino acids were measured during and after graded physical exercise in seven ambulatory patients with well-compensated chronic liver disease and in seven healthy controls. Plasma ammonia was similar in both groups at rest but reached significantly higher peak values (124.0 +/- 29.3 (SD) versus 74.7 +/- 17.7 mumol/l) in the patients with liver disease during exercise. The return to base line during the recovery period was delayed in the patients (T1/2 9.9 +/- 5.5 versus 2.3 +/- 1.0 min). Except for plasma taurine, which was significantly lower in the patients at rest and which showed a significant decrease in the controls but not in the patients during exercise, changes in the plasma concentration of amino acids were similar in the two groups. The increased exposure of patients with chronic liver disease to ammonia while performing an identical workload results from an impaired clearance of ammonia plus, possibly, an increased generation of ammonia in muscle working at a higher intensity. Since hyperammonemia may be associated with the sensation of fatigue, increases in plasma ammonia during daily physical activities might in part explain the easy fatigability often reported by patients with chronic liver disease.
Adult↗
In vivo 31P NMR spectroscopy of energy rich phosphates in the brain of the hyperammonemic rat.
Hyperammonemia is a major contributing factor to the neurological abnormalities observed in hepatic encephalopathy and in congenital defects of ammonia detoxication. In rats variable changes in labile energy rich phosphates in the brain have been observed in hyperammonemia using biochemical methods. Using 31P-NMR spectroscopy however no significant changes of the relative concentrations of the energy rich phosphates alpha, beta and gamma-ATP, phosphocreatine, inorganic phosphate and the pH were found in the fronto parietal cortex of the urease treated hyperammonemic rat. Alterations in the metabolites of these compounds do not appear to be a major pathomechanism of ammonia toxicity in this brain area.
Ammonia↗
Ornithine transcarbamylase deficiency in a male: strict correlation between metabolic control and plasma arginine concentration.
In a male with a partial defect of ornithine transcarbamylase (OTC) we observed that maintenance of arginine supply was crucial for adequate metabolic control in conjunction with a low protein diet. The arginine supplement had to be given such that the concentrations of arginine and ornithine in plasma were above 50 mumol/l. It appears that arginine is needed not only as an essential amino acid for protein synthesis but also as a precursor of ornithine. In this patient the substitution thus aimed at increasing the intramitochondrial ornithine in order to reach a critical substrate concentration for the kinetically abnormal OTC.
Amino Acid Metabolism, Inborn Errors↗
3-Hydroxy-3-methylglutaryl-CoA-lyase deficiency.
Explore the source record for details and available documents.
Blood Glucose↗
Biotinidase deficiency: a cause of subacute necrotizing encephalomyelopathy (Leigh syndrome). Report of a case with lethal outcome.
An unusual clinical course of a patient with biotinidase deficiency, causing Leigh syndrome, is reported. Laryngeal stridor was the major presenting symptom followed by progressive neurologic deterioration and death at the age of 21.5 mo. Absence of skin and hair abnormalities as well as of organic aciduria delayed the correct diagnosis. Necropsy revealed subacute necrotizing encephalopathy (Leigh syndrome). Carboxylase activities (propionyl CoA carboxylase, 3-methylcrotonyl-CoA carboxylase, pyruvate carboxylase) measured in lymphocytes 1 day before death were decreased to 10% of normal values. Propionyl-CoA carboxylase was shown to be the only stable carboxylase in human postmortem tissue; in our patient it was moderately decreased in postmortem liver (29% of control) and kidney (42%), but severely decreased in brain (3%). These findings might explain the severity of neurological symptoms in the absence of marked organic aciduria. They indicate that in biotinidase deficiency the CNS may become biotin depleted earlier and more severely than other organs. Biotinidase deficiency should be included in the differential diagnosis of Leigh syndrome and of unexplained respiratory problems.
Amidohydrolases↗
Vitamins and inherited human errors of metabolism.
Vitamin therapy for inborn errors of metabolism has been used in thiamin-responsive maple syrup urine disease, homocystinuria (pyridoxine-responsive cystathionine synthetase deficiency), disorders of vitamin B12 metabolism and defective methylmalonyl-CoA mutase, biotinidase and holocarboxylase synthetase deficiency, multiple acyl-CoA dehydrogenase deficiency, defective methylene tetrahydrofolate reductase and complex III deficiency (respiratory chain). The inherited defects lead either to alterations of the apoenzymes or to deficiencies of enzymes involved in the processing or reutilization of the vitamins. The application of pharmacological doses of vitamins can be useful in these disorders in order to overcome diminished apoenzyme binding, to saturate residual activities of defective processing enzymes, to compensate for pathological losses, or for acting as electron carriers.
Humans↗
[Carbamyl phosphate synthase deficiency: clinical symptoms, diagnosis and dietary-medicamentous treatment in the neonatal period and infancy].
Carbamyl phosphate synthetase (CPS) catalyses the synthesis of carbamyl-phosphate from ammonia and bicarbonate and is the first step in ureagenesis. The infant described in this report suffered from deficiency of this enzyme. The symptoms started on the 2nd day of life with tachycardia, apathy, irritability and metabolic alcalosis, on the 4th day coma and fits occurred due to hyperammonia (ammonia in the blood max 496 mumol/l, normally up to 150 in newborns). In hepatic tissue no activity of carbamyl phosphate synthetase could be measured (normal range 0.66-2.1 mumol/h/mg protein). Peritoneal dialysis was instituted, but the metabolic crisis could only be overcome by the following therapeutic measures: restriction of protein intake to 1.5 g/kg/d in part as a special aminoacid mixture, in part as breast milk; sufficient caloric supply (600-500 kJ/kg/d); sodium benzoate 350 mg/kg/d: arginine 2 mmol/kg/d respectively citrulline 350 mg/kg/d, and carnitine 150 mg/kg/d. By these procedures the exogenous and endogenous load of ammonia could be minimized. Electroencephalogram and mental development were normal. Acute metabolic crises with hyperammonia during catabolic states (infections) could be treated several times. At the age of 8 months, however, the patient died during such a crisis. This case shows that it is possible to achieve a normal psychomotor development in complete CPS-deficiency by adequate therapy. Catabolic states are difficult to manage.
Amino Acids↗
Determination of medium chain fatty acids in serum.
The determination of medium chain fatty acids in serum is a useful approach of the diagnosis of medium chain acyl-CoA dehydrogenase deficiency, an increasingly recognized cause of Reye-like syndrome in infants. A reliable and practical method requiring 0.5 ml of serum is presented by which results are obtained within 2.5 h. The preparation of the samples is done by solid phase extraction on reverse phase cartridges, the separation and quantitation by gas chromatography. Reference values for children (n = 24) and adults (n = 40) are given for octanoic, decanoic and dodecanoic acids.
Acyl-CoA Dehydrogenase↗
Mitochondrial urea cycle enzymes in rats treated with sodium benzoate.
Since sodium benzoate, which is widely used to treat hyperammonemia its effect on mitochondrial urea cycle enzymes was investigated. its effect on mitochondrial urea cycle enzymes was investigated. Sodium benzoate was administered to urease treated hyperammonemic rats and controls. In both groups no interference with the activity of carbamylphosphate synthetase, ornithine carbamyltransferase and N-acetylglutamate synthetase in the liver could be observed at concentrations of benzoate in plasma found in hyperammonemic patients. Careful monitoring of plasma levels reduces benzoate toxicity as shown in a patient with argininosuccinic aciduria.
Acetyltransferases↗
[Disease course in 20 patients with an early diagnosis of phenylketonuria and hyperphenylalaninemia].
Twenty patients with PKU or hyperphenylalaninemia at ages 0.1 to 15.6 years (median age 6.2 years) were studied prospectively. In all children the condition had been diagnosed when they were neonates on the basis of an abnormal Guthrie test. To maintain plasma phenylalanine levels between 0.2-0.5 mM, dietary restriction of phenylalanine to 20-80 mg/kg daily (median 40 mg/kg) was necessary in 14 children. In children above 8 years, however, these plasma levels were frequently exceeded. In 6 children plasma phenylalanine levels were higher than normal diet. Height, weight and head circumference were within normal range in all patients at all ages. Determinations of DQ/IQ were done at 2, 4, 6 and 8 years of age and revealed values between 90-120 with a median of 102 in the 14 patients who were tested. Only 1 patient had IQ levels between 75-85 and attended special school. Nine other patients were in grade school performing averagely or above. This study confirms that early treatment and long-term follow-up of patients with PKU yield good results. Unsolved problems include duration of dietary treatment and the management of pregnancy in women with PKU.
Adolescent↗
Prenatal diagnosis of carbamoyl-phosphate synthetase deficiency by fetal liver biopsy.
In a pregnancy at risk for carbamoyl-phosphate synthetase (CPS) deficiency, prenatal diagnosis was attempted by fetal liver biopsy, performed at 18 weeks of gestation. CPS activity was absent and the diagnosis was confirmed after termination of the pregnancy. The technique employed for fetal liver biopsy is described together with an evaluation of its possible role in prenatal diagnosis.
Biopsy, Needle↗
DNA analysis of ornithine transcarbamylase deficiency.
By analysing the restriction fragment length polymorphism (RFLP) detected by an ornithinetranscarbamylase (OTC) gene specific DNA probe, we followed the segregation of the defective gene in two families with OTC deficiency (X-linked disease). We were able to exclude some female family members as carriers. In one case a doubtful result obtained in a biochemical carrier detection test (by examining the renal orotic acid excretion after a protein load) could be clarified by DNA analysis. In every family with OTC deficiency, carrier detection should be biochemical with additional DNA analysis. Previous results of the biochemical carrier test should be controlled by DNA analysis, especially when "normal" results were obtained.
Amino Acid Metabolism, Inborn Errors↗