1/19. Branched-chain L-amino acid metabolism in classical maple syrup urine disease after orthotopic liver transplantation.We characterized the effect of orthotopic liver transplantation on the catabolism of branched-chain L-amino acids in a female patient with classical form of maple syrup urine disease. Transplantation was performed at the age of 7.4 years due to a terminal liver failure triggered by a hepatitis a infection. Since then, the patient is on an unrestricted diet and plasma concentrations of branched-chain L-amino and 2-oxo acids are stable, yet at moderately increased levels (2- to 3-fold of control). L-Alloisoleucine concentrations, however, remained remarkably elevated (> 5-fold of control). In vivo catabolism was investigated by measuring the metabolic L-alloisoleucine clearance and whole-body leucine oxidation in the postabsorptive state. In an oral loading test with 580 micromol alloisoleucine per kg body wt, the L-alloisoleucine elimination rate constant (0.067 h(-1)) was in the normal range (0.069 /-0.012 h(-1), n = 4). In an oral L-[1-13C]leucine load (38 micromol/kg body wt), 19.5% of the tracer dose applied was recovered in exhaled 13CO2 versus 18.9 /-3.6% in healthy subjects (n = 10). Thus, the patient exhibited obviously normal whole-body catabolic rates although branched-chain L-amino acid oxidation was confined to the liver transplant. Most likely, the enhanced substrate supply from extrahepatic sources led to an elevation of the plasma concentrations and thus induced a compensatory enhancement of the metabolic flux through the branched-chain 2-oxo acid dehydrogenase complex in the intact liver tissue.- - - - - - - - - - ranking = 1keywords = dehydrogenase (Clic here for more details about this article) |
2/19. Detection of inherited metabolic disorders via tandem mass spectrometry in Thai infants.From a retrospective study in Medical genetics Unit, Department of pediatrics, Siriraj Hospital faculty of medicine, Mahidol University in Bangkok (1983-1988), the estimated pediatric patients with clinically suspected IEM are approximately 2-4% of total annual pediatrics admission of 5,000 or more. This is, a low estimation since survey from all teaching hospitals in the country including the largest Children's Hospital in Bangkok indicated the presence of numerous IEM. However, most IEM were clinically diagnosed with limited laboratory facilities. We started a collaboration with Magee Womens Hospital of Pittsburgh and NeoGen Screening, USA; using tandem mass spectrometry to diagnose high risk infants and children for IEM from July 1993 to March 1998. Of total 146 samples sent, we detected numerous metabolic disorders (11.2%) eg phenylketonuria, organic acidemia, maple syrup urine disease, isovaleric acidemia, methylmalonic acidemia, albinism, translocase/carnitine palmitoyltransferase type II, G6PD deficiency and lysinuric protein intolerance.- - - - - - - - - - ranking = 0.12086790362532keywords = deficiency (Clic here for more details about this article) |
3/19. Utility of hemodialysis in maple syrup urine disease.maple syrup urine disease (MSUD) is an inborn error of metabolism stemming from a deficiency in 2-ketoacid dehydrogenase and resulting in the systemic accumulation of branched chain amino acids (BCAAs). Affected children may suffer profound developmental and cognitive impairment from exposure to high levels of BCAA and their associated neurotoxic metabolites. Endogenous renal clearance of BCAA is limited and several therapeutic modalities including intensive nutritional regimens, exchange transfusions, peritoneal dialysis, and continuous hemofiltration have been utilized in neonates with MSUD, all of which have had varying success in reducing systemic BCAA levels. In this report, a symptomatic 7-day-old 3-kg neonate with MSUD underwent treatment with a combination of early hemodialysis and aggressive enteral feedings of a metabolically appropriate formula. This approach results in a 75% reduction of systemic toxin levels within 3 h. When compared to other reported modalities of therapy for symptomatic neonates with MSUD, this approach appears to be most efficacious. Moreover, by minimizing the amount of time that an affected neonate is exposed to neurotoxic levels of BCAAs, long-term developmental and cognitive capabilities may be preserved.- - - - - - - - - - ranking = 1.1208679036253keywords = dehydrogenase, deficiency (Clic here for more details about this article) |
4/19. maple syrup urine disease presenting with neonatal status epilepticus: report of one case.maple syrup urine disease (MSUD) is a rare inborn error of the branched chain amino acid metabolism, which can be classified as classical, intermediate, intermittent, and thiamine responsive types. We report a 16-day-old boy who suffered from difficult feeding, persistent metabolic acidosis, and tricycling movement of the lower legs. status epilepticus was the initial impression, but classical type MSUD was later diagnosed. Under the diagnosis, dietary therapy effectively prevented further neurological deterioration. However, amino acid deficiency manifested as acrodermatitis enteropathica-like skin rash occurred once. Early parenteral glucose supplementation and periodic plasma amino acid monitoring are very important in the management of metabolic diseases, including MSUD.- - - - - - - - - - ranking = 0.12086790362532keywords = deficiency (Clic here for more details about this article) |
5/19. Changes in the auditory nerve brainstem evoked responses in a case of maple syrup urine disease.maple syrup urine disease (MSUD) is a rare metabolic disease due to deficiency in the enzyme that breaks down branched chain amino acids. Lack of the enzyme causes accumulation of these amino acids and, if untreated, causes severe neurological damage. A case study of a 10-day old female infant, born after 40 weeks' gestation with a birthweight of 2740 g with MSUD hospitalized in the acute stage with respiratory failure and severe brain oedema is described. As part of the neurological evaluation, auditory nerve brainstem evoked response testing was conducted and revealed bilateral presence of the first wave from the auditory nerve, with no later brainstem waves. Over the course of days when her condition improved following dialysis treatment and a diet to reach balanced levels of branched chain amino acids, the later brainstem waves appeared on one side, and several weeks later they were also observed on the other side. The possible mechanisms of the reversibility of the appearance of brainstem waves in this case are discussed.- - - - - - - - - - ranking = 0.12086790362532keywords = deficiency (Clic here for more details about this article) |
6/19. Amino acid clearance during acute metabolic decompensation in maple syrup urine disease treated with continuous venovenous hemodialysis with filtration.OBJECTIVE: Assessment of amino acid clearances by continuous venovenous hemodialysis with filtration in treatment of a metabolic decompensation in acute maple syrup urine disease. DESIGN: Single patient assessment. SETTING: Pediatric intensive care unit. patients: A 10-yr-old male with known maple syrup urine disease (branched chain alpha-ketoacid dehydrogenase deficiency) with metabolic decompensation due to an acute viral illness, characterized by altered mental status, progressive obtundation, and severe acidosis. INTERVENTIONS: Continuous venovenous hemodialysis with filtration. MEASUREMENTS AND MAIN RESULTS: Continuous venovenous hemodialysis with filtration was instituted with both filtration (500 mL/m(2)/hr) and dialysis (1000 mL/m(2)/hr) utilized, allowing rapid correction of systemic ketoacidosis while providing amino acid clearance. Amino acid clearance was measured at initiation and at 24 hrs into therapy. The procedure was well tolerated, with near normal mental status within 12 hrs and resumption of enteral feedings. During the 24-hr period of continuous venovenous hemodialysis with filtration, serum leucine levels fell from 2352 to 381 micromoles/L, isoleucine fell from 626 to 164, and valine fell from 1117 to 228. Leucine, isoleucine, and valine clearance rates averaged 13.1, 12.8, and 13.2 mL/min, respectively, and were constant during the 24 hrs of treatment. Clearance of other amino acids during this period did not vary significantly between cationic, anionic, neutral, or hydrophobic amino acids. CONCLUSIONS: Continuous venovenous hemodialysis with filtration provides an effective therapeutic alternative to intermittent hemodialysis during acute metabolic decompensation in maple syrup urine disease.- - - - - - - - - - ranking = 3.9256607017766keywords = dehydrogenase deficiency, dehydrogenase, deficiency (Clic here for more details about this article) |
7/19. Diagnosis of MSUD by newborn screening allows early intervention without extraneous detoxification.maple syrup urine disease (MSUD) is a genetic metabolic disorder resulting from the defective activity of branched-chain 2-ketoacid dehydrogenase complex. Due to the metabolic block, high concentrations of the branched-chain amino acids (BCAA) leucine, valine, isoleucine, and allo-isoleucine as well as their corresponding branched-chain 2-keto acids accumulate in patients on a BCAA-unrestricted diet or during episodes with increased protein catabolism. early diagnosis and management are essential to prevent permanent brain damage. Newborn screening by tandem MS allows for detection of elevated BCAA concentrations in blood in patients with classical MSUD before they show severe encephalopathic symptoms. Here, we report that newborn screening by expanded tandem MS enables for reversing the intoxication in newborns with MSUD within 24-48 h without any need for extraneous detoxification and thus decreasing the risk of brain damage during a particularly vulnerable period.- - - - - - - - - - ranking = 1keywords = dehydrogenase (Clic here for more details about this article) |
8/19. Abnormal dendritic development in maple syrup urine disease.The neuropathology of a 6-year-old boy with maple syrup urine disease revealed spongy appearance of the white matter and marked edema of the brainstem. Golgi studies demonstrated aberrant orientation of neurons together with abnormalities of dendrites and dendritic spines. Similar changes were observed in a patient with dihydropteridine reductase deficiency. Disorders of amino acid metabolism may be associated with alterations in the terminal stages of neuronal migration and maturation.- - - - - - - - - - ranking = 0.12086790362532keywords = deficiency (Clic here for more details about this article) |
9/19. Atypical phenotype in a boy with a maple syrup urine disease.maple syrup urine disease (MSUD) is a metabolic disorder due to a block in the decarboxylation step in the catabolic pathways of the branched-chain amino acids (BCAAs). We describe an atypical presentation in an infant male. The patient presented with psychomotor retardation, profound hypotonia and elevated plasma levels of BCAAs, but no elevation of alloisoleucine. Cranial magnetic resonance imaging showed prominent diffuse CSF spaces, delayed myelin maturation and symmetrical signal abnormality within the globi pallidi, midbrain, dorsal pons and medulla. The cerebellar white matter was specifically spared. A mitochondrial disorder was suggested. After correction of feeding problems with G-tube feeds, his high BCAAs persisted and, on fourth analysis, alloisoleucine was seen. Subsequent fibroblast enzyme and mutation analysis confirmed MSUD due to E(1)-alpha subunit deficiency. After starting dietary treatment, there was no significant improvement in his hypotonia or his psychomotor development. However, the high signal within the globi pallidi had resolved. MSUD may have diverse clinical presentations, and should be considered in children who present with chronic psychomotor delay but no acute encephalopathic episodes. BCAA levels may not be very high, alloisoleucine may not always be detected in MSUD even with severe enzyme deficiency, and imaging may be misleading if seen in the chronic phase only.- - - - - - - - - - ranking = 0.24173580725063keywords = deficiency (Clic here for more details about this article) |
10/19. Metabolic correlates of learning disability.To summarize, the neuropsychologic findings in MSUD and MMA children in both groups demonstrated deficits in cognitive/language areas, but interesting individual differences existed. For example, a marked contrast in abilities existed between NT and GV, even taking into account the age difference between these children with MSUD. While NT's general intellectual functioning was within the low-average range, GV was severely impaired. In more specific areas of cognitive functioning, NT had an uneven performance profile with areas of strengths and weaknesses, while GV evidenced a flat profile with significant impairment in all areas. NT demonstrated mild delay in visual-spatial processing, articulation development, motor-speech abilities, and selective attention and concentration; however, his language and psychosocial development were within the broad range of normality. In contrast, GV exhibited severe dysfunction in speech, language, and perceptual/conceptual development. The three children with MMA also exhibited a range of disabilities in cognitive functioning. TJ and SH contrasted in the degree of developmental delay across language and cognitive domains. Both were distractible and exhibited very short attention spans but there was a measurable difference in the extent of their speech, language, visual-spatial development. CH was markedly delayed in all areas of cognitive development, which is consistent with global retardation. The severity of her disease and its probable impact on brain development were undoubtedly related to her intellectual impairment. These datasets illustrate the challenges we face, because within each group we see a range of impairment. Nevertheless, we are optimistic that our efforts to relate metabolic, anatomic and neuropsychologic findings for such children will lead to a better understanding of these disorders. We are hopeful that this will result in new advances in diagnosis and intervention, which will ultimately improve the prognosis for cognitive development. In summary, a multidisciplinary center has been established at UCSD to study the neurologic basis of disorders of language, learning and behavior in infants and children. The center draws together a group of researchers from many fields including neurology, biochemistry, pediatrics, cognitive and developmental neuropsychology, psycholinguistics, neurophysiology and communicative disorders. Because of the diverse interests and expertise of our group, it is hoped to forge a synthesis of the behavioral and neurosciences to study populations of children with a variety of neurologic, metabolic, and language/learning disorders. Disorders currently under study include Lesch-Nyhan disease, oculocutaneous tyrosinemia, propionic acidemia, carnitine palmityl transferase deficiency, Schwachman-diamond syndrome, histidinemia, hartnup disease, citrullinemia, galactosemia, maple syrup urine disease, and methylmalonic acidemia.(ABSTRACT TRUNCATED AT 400 WORDS)- - - - - - - - - - ranking = 0.12086790362532keywords = deficiency (Clic here for more details about this article) |
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