Navegando por Palavras-chave "CBS"

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    The p.T191M mutation of the CBS gene is highly prevalent among homocystinuric patients from Spain, Portugal and South America
    (Springer, 2006-01-01) Urreizti, Roser; Asteggiano, Carla; Bermudez, Marta; Cordoba, Alfonso; Szlago, Marina; Grosso, Carola; Kremer, Raquel Dodelson de; D'Almeida, Vânia [UNIFESP]; Martinez-Pardo, Mercedes; Pena-Quintana, Luis; Dalmau, Jaime; Rodes, Marta; Vilaseca, Maria Antonia; Balcells, Susana; Grinberg, Daniel; Univ Barcelona; Univ Nacl Cordoba; Pontificia Univ Javeriana; Univ Antioquia; Fundac Estud Enfermedades Neurometab; Inst Genet Med Jacinto Magalhaes; Universidade Federal de São Paulo (UNIFESP); Hosp Ramon y Cajal; Hosp Univ Materno Infantil; Hosp Infantil Le Fe; Hosp Clin Univ Santiago; Corp Sanitaria Clin; Hosp St Joan Deu
    Classical homocystinuria is due to cystathionine beta-synthase (CBS) deficiency. More than 130 mutations, which differ in prevalence and severity, have been described at the CBS gene. Mutation p.I278T is very prevalent, has been found in all European countries where it has been looked for with the exception of the Iberian peninsula, and is known to respond to vitamin B-6. On the other hand, mutation p.T191M is prevalent in Spain and Portugal and does not respond to B-6. We analysed 30 pedigrees from Spain, Portugal, Colombia and Argentina, segregating for homocystinuria. the p.T191M mutation was detected in patients from all four countries and was particularly prevalent in Colombia. the number of p.T191M alleles described in this Study, together with those previously published, is 71. the prevalence of p.T191M among CBS mutant alleles in the different countries was: 0.75 in Colombia, 0.52 in Spain, 0.33 in Portugal, 0.25 in Venezuela, 0.20 in Argentina and 0.14 in Brazil. Haplotype analyses suggested a double origin for this mutation. No genotype-phenotype correlation other than the B-6-nonresponsiveness Could be established for the p.T191M mutation. Additionally,. three new mutations, p.M173V, p.I429del and c.69_70+8de110, were found. the p.M173V was associated with a mild, B-6-responsive, phenotype.
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    Relationship between polymorphisms in genes involved in homocysteine metabolism and maternal risk for Down syndrome in Brazil
    (Wiley-Blackwell, 2005-06-15) Silva, LRJ da; Vergani, N.; Galdieri, L. D.; Porto, MPR; Longhitano, S. B.; Brunoni, D.; D'Almeida, V; Perez, ABA; Universidade Federal de São Paulo (UNIFESP); Assoc Pais & Amigos Excepcionais
    Associations between specific alleles of genes encoding enzymes in the methionine/homocysteine pathway and plasma homocysteine levels have been examined in different populations. in the present study, we determined polymorphisms of MTHFR A222V (677C > T), MTHFR E429A (1298A > C), MTRR I22M (66A > G), MTR D919G (2756A > G), and CBS 844ins68 and total plasma homocysteine levels (tHcy) among 154 mothers of children with Down syndrome (DS) and 158 control mothers from Brazil. Homocysteine levels were higher among DS mothers compared to control groups (10.437 vs. 8.600 respectively, P = 0.002). Only the 677T allele was associated with altered levels of tHcy in the case group (F(2,153) = 5.300; P = 0.006), primarily when homozygous. in the control group, the association of the TT genotype with higher levels of tHcy showed borderline significance (F(2,157) = 2.974; P = 0.054). All genotype distributions were similar in the two groups (P > 0.05), but the frequency of the 677T allele in the case group was significantly higher (X-2 = 3.862; DF = 1; P = 0.049; OR = 1.437 (1.001-2.062)). Although the 677T allele is associated with increased homocysteine levels, its presence has only a modest impact as an independent risk factor for DS. All the other polymorphisms did not show an association with risk for the syndrome, when evaluated separately (P > 0.05). However, when the presence of 677T, 1298C, 2756G, 66G, and 844ins68 alleles were evaluated together, the mothers of children with DS tend to have a higher number of uncommon alleles than the mothers with no previous affected child. (c) 2005 Wiley-Liss, Inc.