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Salvarinova-Zivkovic R.,UBC | Hartnett C.,UBC | Sinclair G.,Biochemical Genetics Laboratory | Dix D.,UBC | And 3 more authors.
Molecular Genetics and Metabolism | Year: 2012

The metabolic control of phenylalanine levels is a challenge during illness. We present the metabolic management of a 6. year old boy with classical PKU who was diagnosed with stage III intraabdominal Burkit's lymphoma and underwent surgical resection and chemotherapy. The metabolic control during chemotherapy was achieved by the use of parenteral custom made amino acid solution and pro-active adjustment of intake. From the 94 obtained plasma phenylalanine (Phe) levels, 18.4% were above our clinic's recommended upper limit (360. μmol/L, 6. mg/dL) while 52.7% of Phe levels were below the recommended lower limit (120. μmol/L, 2. mg/dL). Phe levels above recommended range were associated with low caloric/protein intake, while levels below recommended range reflected the difficulty in achieving the full prescribed Phe intake. We recommend early institution of custom made amino acid solution with maximum amino acid content and caloric intake to provide optimal phenylalanine control. Administration of phenylalanine via regular intravenous amino acid solution may assist in avoiding low Phe levels when prescribed intake is compromised due to vomiting and other disease related illnesses.Use of custom made, phenylalanine free amino acid solution proved beneficial in the management of blood phenylalanine levels in a PKU patient during chemotherapy for Burkitt lymphoma. © 2012 Elsevier Inc..

Burrage L.C.,Case Western Reserve University | Burrage L.C.,University Hospitals Case Medical Center | Baskin-Hill A.E.,Case Western Reserve University | Sinasac D.S.,Case Western Reserve University | And 10 more authors.
Mammalian Genome | Year: 2010

Discovery of genes that confer resistance to diseases such as diet-induced obesity could have tremendous therapeutic impact. We previously demonstrated that the C57BL/6J-ChrA/J/NaJ panel of chromosome substitution strains (CSSs) is a unique model for studying resistance to diet-induced obesity. In the present study, three replicate CSS surveys showed remarkable consistency, with 13 A/J-derived chromosomes reproducibly conferring resistance to high-fat-diet-induced obesity. Twenty CSS intercrosses, one derived from each of the 19 autosomes and chromosome X, were used to determine the number and location of quantitative trait loci (QTLs) on individual chromosomes and localized six QTLs. However, analyses of mean body weight in intercross progeny versus C57BL/6J provided strong evidence that many QTLs discovered in the CSS surveys eluded detection in these CSS intercrosses. Studies of the temporal effects of these QTLs suggest that obesity resistance was dynamic, with QTLs acting at different ages or after different durations of diet exposure. Thus, these studies provide insight into the genetic architecture of complex traits such as resistance to diet-induced obesity in the C57BL/6J-ChrA/J/NaJ CSSs. Because some of the QTLs detected in the CSS intercrosses were not detected using a traditional C57BL/6J × A/J intercross, our results demonstrate that surveys of CSSs and congenic strains derived from them are useful complementary tools for analyzing complex traits. © 2010 Springer Science+Business Media, LLC.

Mercimek-Mahmutoglu S.,University of Toronto | Cordeiro D.,University of Toronto | Cruz V.,University of Toronto | Hyland K.,Medical Neurogenetics LLC | And 3 more authors.
European Journal of Paediatric Neurology | Year: 2014

Background and hypothesis Pyridoxine dependent epilepsy (PDE) due to mutations in the ALDH7A1 gene (PDE-ALDH7A1) is caused by α-aminoadipic-semialdehyde-dehydrogenase enzyme deficiency in the lysine pathway resulting in the accumulation of α-aminoadipic acid semialdehyde (α-AASA). Classical presentation is neonatal intractable seizures with a dramatic response to pyridoxine. Pyridoxine therapy does not prevent developmental delays in the majority of the patients. We hypothesized that l-arginine supplementation will decrease accumulation of α-AASA by competitive inhibition of lysine transport into the central nervous system and improve neurodevelopmental and neurocognitive functions in PDE-ALDH7A1.Methods A 12-year-old male with PDE-ALDH7A1 was treated with l-arginine supplementation as an innovative therapy. Treatment outcome was monitored by cerebral-spinal-fluid (CSF) α-AASA measurements at baseline, 6th and 12th months of therapy. Neuropsychological assessments were performed at baseline and 12th months of therapy.Results l-arginine therapy was well tolerated without side effects. CSF α-AASA was decreased 57% at 12th months of therapy. Neuropsychological assessments revealed improvements in general abilities index from 108 to 116 and improvements in verbal and motor functioning at 12th months of therapy.Conclusion The short-term treatment outcome of this novel l-arginine supplementation therapy for PDE-ALDH7A1 was successful for biochemical and neurocognitive improvements. © 2014 European Paediatric Neurology Society.

Wei X.-C.,University of Calgary | Snyder F.F.,Biochemical Genetics Laboratory | Mah J.K.,University of Calgary | Waterham H.,University of Amsterdam | Wanders R.J.A.,University of Amsterdam
Neuroradiology | Year: 2010

We report serial neurodegenerative changes on neuroimaging in a rare peroxisomal disease called D-bifunctional protein deficiency. The pattern of posterior to anterior demyelination with white matter disease resembles X-linked adrenoleukodystrophy. We feel this case is important to (1) highlight that D-bifunctional protein deficiency should be considered in cases where the neuroimaging resembles X-linked adrenoleukodystrophy, (2) to show different stages of progression to help identify this disease using neuroimaging in children, and (3) to show that neuroimaging suggesting a leukodystrophy can warrant peroxisomal beta-oxidation studies in skin fibroblasts even when plasma very long chain fatty acids are normal. © 2010 Springer-Verlag.

Mercimek-Mahmutoglu S.,University of British Columbia | Mercimek-Mahmutoglu S.,University of Toronto | Horvath G.A.,University of British Columbia | Coulter-Mackie M.,University of British Columbia | And 7 more authors.
Pediatrics | Year: 2012

Pyridoxine-dependent epilepsy (PDE) was first described in 1954. The ALDH7A1 gene mutations resulting in a-aminoadipic semialdehyde dehydrogenase deficiency as a cause of PDE was identified only in 2005. Neonatal epileptic encephalopathy is the presenting feature in >50% of patients with classic PDE. We report the case of a 13-month-old girl with profound neonatal hypoglycemia (0.6 mmol/L; reference range >2.4), lactic acidosis (11 mmol/L; reference range <2), and bilateral symmetrical temporal lobe hemorrhages and thalamic changes on cranial MRI. She developed multifocal and myoclonic seizures refractory to multiple antiepileptic drugs that responded to pyridoxine. The diagnosis of α-aminoadipic semialdehyde dehydrogenase deficiency was confirmed based on the elevated urinary a-aminoadipic semialdehyde excretion, compound heterozygosity for a known splice mutation c.834G>A (p.Val278Val), and a novel putative pathogenic missense mutation c.1192G>C (p.Gly398Arg) in the ALDH7A1 gene. She has been seizure-free since 1.5 months of age on treatment with pyridoxine alone. She has motor delay and central hypotonia but normal language and social development at the age of 13 months. This case is the first description of a patient with PDE due to mutations in the ALDH7A1 gene who presented with profound neonatal hypoglycemia and lactic acidosis masquerading as a neonatal-onset gluconeogenesis defect. PDE should be included in the differential diagnosis of hypoglycemia and lactic acidosis in addition to medically refractory neonatal seizures. Copyright © 2012 by the American Academy of Pediatrics.

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