title: Galactose oxidation using (13)C in healthy and galactosemic children.
abstract: Galactosemia is an inborn error of galactose metabolism that occurs mainly as the outcome of galactose-1-phosphate uridyltransferase (GALT) deficiency. The ability to assess galactose oxidation following administration of a galactose-labeled isotope (1-(13)C-galactose) allows the determination of galactose metabolism in a practical manner. We aimed to assess the level of galactose oxidation in both healthy and galactosemic Brazilian children. Twenty-one healthy children and seven children with galactosemia ranging from 1 to 7 years of age were studied. A breath test was used to quantitate (13)CO2 enrichment in exhaled air before and at 30, 60, and 120 min after the oral administration of 7 mg/kg of an aqueous solution of 1-(13)C-galactose to all children. The molar ratios of (13)CO2 and (12)CO2 were quantified by the mass/charge ratio (m/z) of stable isotopes in each air sample by gas-isotope-ratio mass spectrometry. In sick children, the cumulative percentage of (13)C from labeled galactose (CUMPCD) in the exhaled air ranged from 0.03% at 30 min to 1.67% at 120 min. In contrast, healthy subjects showed a much broader range in CUMPCD, with values from 0.4% at 30 min to 5.58% at 120 min. The study found a significant difference in galactose oxidation between children with and without galactosemia, demonstrating that the breath test is useful in discriminating children with GALT deficiencies.
authors.affiliation: Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: D R
authors.initials: DR
authors.lastname: Resende-Campanholi
authors.affiliation: Unidade de Hepatologia Pediátrica, Instituto da Criança Prof. Pedro de Alcântara, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: G
authors.initials: G
authors.lastname: Porta
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: E
authors.initials: E
authors.lastname: Ferrioli
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: K
authors.initials: K
authors.lastname: Pfrimer
authors.affiliation: Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: L A Del
authors.initials: LA
authors.lastname: Ciampo
authors.affiliation: Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: J S Camelo
authors.initials: JS
authors.lastname: Junior
mesh_terms: D001944:Breath Tests; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005690:Galactose / Q000378:metabolism*; D005693:Galactosemias / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007223:Infant; D008297:Male; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D012372:ROC Curve; D005694:UTP-Hexose-1-Phosphate Uridylyltransferase / Q000235:genetics / Q000378:metabolism*
chemical_list: D005694:UTP-Hexose-1-Phosphate Uridylyltransferase; D005690:Galactose