Hereditary defect of cobalamin metabolism (cblG mutation) presenting as a neurologic disorder in adulthood.
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Biomedical subjects
Publications and source records attributed to S I Goodman.
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A child presenting with mild psychomotor retardation, hypotonia, microcephaly and hyperkinesis is described. Urinary organic acid analysis by combined gas chromatography-mass spectrometry revealed 4-hydroxybutyric aciduria. Succinic semialdehyde dehydrogenase activity in extracts of white cells derived from the patient was less than 10% of control values.
The neuropathology in three cases of glutaric acidaemia type 1 is presented. All three showed extensive neuronal loss in the caudate nucleus and the putamen, with only small numbers of large neurons surviving. The globus pallidus showed moderate shrinkage and gliosis but no conspicuous decreases in neurons. Severe spongiform change was seen in many regions, involving predominantly white matter. These features are very similar to some cases described previously in familial striatal degeneration in childhood, but are different from other cases. If found in a brain at autopsy, they should lead to studies to diagnose glutaric acidaemia type 1 retrospectively, so that accurate genetic counselling and prenatal diagnosis in future pregnancies can be offered.
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Neurotransmitter amino acids were measured in post-mortem caudate nucleus, nucleus accumbens, frontal cortex, amygdala, and hypothalamus of chronic schizophrenic and normal control subjects. The concentrations of upsilon-aminobutyric acid (GABA), taurine, glycine-threonine, glutamate, aspartate, glutamine, tryptophan, and alanine were similar in both groups, with the exception of decreased GABA and tryptophan in the amygdala of the schizophrenic group. Strong positive correlations were obtained between the concentration of tryptophan, a putative agonal status marker of post-mortem brain tissue, and the concentration of GABA in all brain areas. When the GABA concentrations were adjusted for tryptophan concentrations in amygdala, the difference between the schizophrenic and control samples was no longer significant, suggesting that the original difference may have been due to different agonal or post-mortem changes in the tissues. There were, however, no significant correlations between GABA and post-mortem interval. The present results do not support the aminoacidergic hypotheses of chronic schizophrenia, although a GABA deficiency cannot be entirely excluded.
Glutaric acidemia, which is due to inherited deficiency of glutaryl-CoA dehydrogenase, is characterized clinically by progressive dystonia and dyskinesia in childhood, and pathologically by degeneration of the caudate and putamen. Results using newer imaging techniques (computer tomography and magnetic resonance image scanning) suggest that neurological involvement in this condition begins before birth, and that gliosis of the basal ganglia is a relatively late event. Glutaric acidemia type II is usually due to inherited deficiency of electron transfer flavoprotein (ETF) or ETF:ubiquinone oxidoreductase, but some patients with typical disease may have another, to date undefined, abnormality. There may also be a clinical phenotype of glutaric acidemia type II which, like glutaryl-CoA dehydrogenase deficiency, is characterized by a movement disorder and by degeneration of the basal ganglia.
The present study was planned to test a recent observation of positive correlation between tryptophan and 5-hydroxyindole concentrations in postmortem human hypothalamic samples. Four other brain areas were studied, but no significant correlations were observed between tryptophan and serotonin or 5-hydroxyindoleacetic acid concentrations, except in the nucleus accumbens samples of a suicide victim group. A possible in vivo correlation may have been obscured by postmortem changes. The use of tryptophan concentrations as an index for normalising postmortem brain serotonin data is not supported by the present results.
Glutaryl-CoA dehydrogenase, a multifunctional enzyme responsible for dehydrogenation and decarboxylation of glutaryl-CoA to crotonyl-CoA, has been purified 1,680-fold from porcine liver mitochondria. The purified porcine enzyme has a subunit molecular weight of 47,800 and a native molecular weight of 190,500. Porcine glutaryl-CoA dehydrogenase catalyzed the conversion of [1,5-14C]glutaryl-CoA to [14C] crotonyl-CoA and 14CO2 in a 1:1:1 ratio. The porcine enzyme has Km values for electron transfer flavoprotein and glutaryl-CoA of 1.1 and 3.3 microM, respectively, and turnover numbers of 860 mol of electron transfer flavoprotein/min/mol of glutaryl-CoA dehydrogenase and 327 mol of glutaryl-CoA/min/mol of glutaryl-CoA dehydrogenase. Human glutaryl-CoA dehydrogenase has been purified 1,278-fold from human liver mitochondria. The purified human enzyme has a subunit molecular weight of 58,800 and a native molecular weight of 256,000. Human glutaryl-CoA dehydrogenase showed a reaction of only partial identity when compared to porcine glutaryl-CoA dehydrogenase by Ouchterlony double immunodiffusion analysis using antiserum raised against and monospecific for porcine glutaryl-CoA dehydrogenase.
Serotonin (5-HT) and 5-hydroxyindoleacetic acid concentrations were determined in various brain areas of nonschizophrenic suicide victims, chronic schizophrenic patients with or without suicide as the cause of death, and normal control subjects without psychiatric or neurologic disorders. Serotonin concentrations in the basal ganglia were significantly elevated in suicide victims and chronic schizophrenic patients, as were 5-hydroxyindoleacetic acid concentrations in the occipital cortex. These differences were not specific to either patient group and may have been caused by neuroleptic or antidepressant treatment. A decreased 5-HT concentration was found in the hypothalamus of nonschizophrenic suicide victims. Among the chronic schizophrenic patients, there was no significant difference in the hypothalamic 5-HT content between the suicide victims and others, indicating that low 5-HT levels in the hypothalamus are not characteristic of schizophrenic patients who died of suicide.
A stable isotope dilution method was developed to measure accurately small amounts of isovalerylglycine in amniotic fluid and urine for the prenatal diagnosis of isovaleric acidemia. [4,4,4-D3]Isovalerylglycine was synthesized and used as an internal standard. Samples were extracted, methylated, and analyzed by chemical ionization gas chromatography-mass spectrometry operated in the selected ion monitoring mode. This method is very sensitive (lower limit approximately 5 ng/ml), linear over three orders of magnitude above 10 ng/ml up to at least 10 micrograms/ml and reproducible. No isovalerylglycine was detected at all in amniotic fluids from eleven normal pregnant women with an exception of a single case which contained 6 ng/ml. Amniotic fluids from five pregnancies at risk were analyzed. Two of these samples had isovalerylglycine concentrations of 957 and 556 ng/ml. Three others contained 18, 18, and 17 ng/ml of isovalerylglycine. Postpartum diagnostic tests and/or in vitro assay of isovaleryl-CoA dehydrogenase of [1-14C] isovaleric acid oxidation using amniocytes confirmed that the first two fetuses were affected by isovaleric acidemia, whereas the latter three were unaffected. The method described in this report provides a highly accurate and reliable technique for the prenatal diagnosis of isovaleric acidemia.
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A fluorimetric, ETF-linked procedure to determine activities of acyl-CoA dehydrogenase in cultured human fibroblasts is described. The assay readily distinguishes between cell lines deficient in medium-chain acyl-CoA dehydrogenase, long-chain acyl-CoA dehydrogenase, isovaleryl-CoA dehydrogenase, and controls, and may allow for the diagnosis of heterozygous carriers of these disorders. The method has been made feasible with the development of rapid and efficient procedures to isolate ETF, and offers several advantages over procedures that are currently employed.
Glutaric acidemia type II (GA II) is a human genetic disorder. It has been suggested that the primary defect in this disorder is a deficiency of a protein involved in electron transport between the acyl-CoA dehydrogenases and the bc1 complex of the mitochondrial respiratory chain. Antisera were raised to purified porcine electron transfer flavoprotein (ETF) and electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO). The antisera were used to detect the two electron transferases in control and GA II fibroblasts by immunoblotting. Fibroblasts from three unrelated GA II patients were deficient in immunologically detectable ETF:QO and extracts from these three fibroblast lines contained no detectable ETF:QO catalytic activity. Fibroblasts from parents of two of these patients had ETF:QO activity intermediate between activities in control fibroblasts and fibroblasts from the patients. These data indicate that the primary defect in these patients is a deficiency of ETF:QO and that the mode of transmission of the gene is autosomal recessive. Fibroblasts from two other patients with severe GA II had normal levels of ETF-QO activity and antigen but were deficient in immunoreactive ETF. These findings show that GA II results from a deficiency of ETF in some patients and ETF:QO in others. In addition, these investigations provide strong evidence for the specificity and physiological function of the iron-sulfur flavoprotein ETF:QO.
Three children from unrelated families presented in early childhood with hypoglycemia and cardiorespiratory arrests associated with fasting. Significant hepatomegaly, cardiomegaly, and hypotonia were present at the time of initial presentation. Ketones were not present in the urine at the time of hypoglycemia in any patient; however, dicarboxylic aciduria was documented in one patient at the time of the acute episode and in two patients during fasting studies. Total plasma carnitine concentration was low with an increased esterified carnitine fraction. These findings suggested a defect in mitochondrial fatty acid oxidation, and specific assays were performed for the acyl coenzyme A (CoA) dehydrogenases. These analyses showed that the activity of the long-chain acyl CoA dehydrogenase was less than 10% of control values in fibroblasts, leukocytes, and liver tissue. Activities of the medium-chain, short-chain, and isovaleryl CoA dehydrogenases were not different from control values. With cultured fibroblasts, CO2 evolution from long-chain fatty acids was significantly reduced, while CO2 evolution from medium-chain and short-chain fatty acids was comparable to control values--findings consistent with a defect early in the beta-oxidation sequence. Studies of acyl CoA dehydrogenase activities in fibroblasts and leukocytes from parents of the patients showed levels of long-chain acyl CoA dehydrogenase activity intermediate between affected and control values and indicated an autosomal recessive form of inheritance of this enzymatic defect.(ABSTRACT TRUNCATED AT 250 WORDS)
The clinical and biochemical phenotype of glutaric acidaemia type II (GAII) has led to the suggestion that the defect in the disorder affects electron transfer from primary FAD-containing dehydrogenases into the respiratory chain. Two proteins are involved in this process, i.e. electron transfer flavoprotein (ETF) and ETF dehydrogenase, an iron--sulphur flavoprotein with a distinctive EPR signal. Reliable catalytic assays for these proteins are not available, but both proteins have been purified and antisera against them prepared in rabbits. SDS-PAG electrophoresis of liver mitochondrial membranes from a GAII infant with congenital anomalies, locating ETF dehydrogenase with specific antiserum, showed no cross-reactive material. EPR of the same membranes showed a marked decrease in the ETF dehydrogenase signal. These results suggest that the defect in GAII in some patients is indeed in electron transport, and specifically in ETF dehydrogenase.
Oral administration of hypoglycin (5-6 mg/100 g body wt) to weanling rats produces, in addition to the well-recognized organic aciduria, pronounced iminoacidemia, hyperiminoacidura, and decreased activity of proline and hydroxyproline oxidases.
An 8-month-old boy with severe lactic acidosis was found to have lipoamide dehydrogenase deficiency. Treatment with thiamine, biotin, bicarbonate, protein restriction, and ketogenic diet failed to alleviate the lactic acidosis. Oral administration of lipoic acid 25 to 50 mg/kg produced dramatic improvement in lactic and pyruvic acidemia, which has continued for 2 years and which has been accompanied by clinical improvement.
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