RESUMO
Phenylalanine hydroxylase deficiency is a trait inherited in an autosomal recessive pattern; the associated phenotype varies considerably. This variation is mainly due to the considerable allelic heterogeneity in the phenylalanine hydroxylase enzyme locus. We examined the genotype-phenotype correlation in 54 phenylketonuria (PKU) patients from Minas Gerais, Brazil. Two systems were used. The first was a phenotype prediction system based on arbitrary values (AV) attributed to each mutation and the second was a correlation analysis. An AV was assigned to each mutation: AV = 1 for classical PKU mutation; AV = 2 for moderate PKU mutation; AV = 4 for mild PKU mutation, and AV = 8 for non-PKU hyperphenylalaninemia mutation. The observed phenotype for AV analysis was the clinical diagnosis established by the overloading phenylalanine test. Among the 51 PKU patients that we analyzed based on this trait, in 51% the predicted phenotype did not match the observed phenotype; the highest degree of concordance was found in patients with null/null genotypes. The genotype was observed to be a good predictor of the clinical course of the patients and significant correlations were found between phenylalanine values at first interview and predicted residual activity, genotype and arbitrary value sum.
Assuntos
Variação Genética , Fenilalanina Hidroxilase/genética , Fenilcetonúrias/genética , Sequência de Aminoácidos , Brasil , Genótipo , Humanos , Lactente , Mutação , Fenótipo , Fenilcetonúrias/enzimologia , Índice de Gravidade de DoençaRESUMO
This work was undertaken in order to ascertain the PKU mutational spectrum in Minas Gerais, Brazil, the relative frequency of the mutations in the State and the origin of these mutations by haplotype determination. Minas Gerais is a trihybrid population formed by miscegenation from Europeans, Africans and Amerindians. All 13 exons of the PAH gene from 78 PKU patients were analyzed, including splicing sites and the promoter region. We identified 30 different mutations and 98% of the PAH alleles were established. A new mutation (Q267X) was identified as well. The most common mutations found were V388M (21.2), R261Q (16.0%), IVS10-11G>A (15.3%), I65T (5.8%), IVS2+5G>C (5.8%), R252W (5.1%), IVS2+5G>A (4.5%), P281L (3.8%) and L348V (3.2%). These nine mutations correspond to 80% of the PKU alleles in the state. Haplotypes were determined to characterize the origin of the PAH alleles. The majority of the mutations found, with respective haplotypes, are frequent in the Iberian Peninsula. However, there were some mutations that are rare in Europe and four previously unreported mutation-haplotype associations. I65T and Q267X were found in association with haplotype 38 and may be African in origin or the result of miscegenation in the Brazilian population.
Assuntos
Mutação , Fenilalanina Hidroxilase/genética , Fenilcetonúrias/genética , Substituição de Aminoácidos , Brasil/epidemiologia , Análise Mutacional de DNA , Humanos , Fenilcetonúrias/epidemiologiaRESUMO
In order to determine the phenylketonuria (PKU) mutation spectrum in the population of Minas Gerais State, Brazil, 78 unrelated PKU patients found by the neonatal screening program from 1993 to 2003 were tested for nine phenylalanine hydroxylase mutations. These mutations were selected due to their high frequencies in other Brazilian populations and in Portugal, where the largest contingent of the Caucasian component of the Brazilian population originated from. The most frequent mutations were V388M (21%), R261Q (16%), IVS10nt11 (13.4%), I65T (5.7%), and R252W (5%). The frequencies of the other four mutations (R261X, R408W, Y414C, and IVS12nt1) did not reach 2%. By testing these nine mutations, we were able to identify 64% of the PKU alleles in our sample. V388M frequency was higher than in any other known population and almost three times larger than that observed in Portugal, probably reflecting genetic drift. The mutation profile, as well as the relative frequency of the different mutations, suggest that the Minas Gerais population more closely resembles that of Portugal than do the other Brazilian populations that have already been tested.
Assuntos
Humanos , Recém-Nascido , Fenilalanina Hidroxilase/genética , Fenilcetonúrias/genética , Mutação/genética , Testes Genéticos , Brasil/epidemiologia , Eletroforese em Gel de Poliacrilamida , Fenilcetonúrias/epidemiologia , Triagem NeonatalRESUMO
The yeast two-hybrid system is a powerful tool for screening protein-protein interactions and has also been used for large-scale studies. We evaluated two protein-coding sequences as reporter genes for the yeast two-hybrid system, to determine if it was suitable as an alternative screening strategy. Aspergillus awamori glucoamylase activity results in clear haloes around colonies producing this enzyme after growth on starch plates and staining with iodine vapors. However, transcription activation by Gal4 on Gal-regulated promoters was insufficient for this type of phenotypic visualization. A modified gene of Aequoria victoria enhanced green fluorescent protein (EGFP) was tested to determine its suitability for interaction screenings with flow cytometry. When the EGFP reporter gene system was incorporated into the cells, Gal4 transcriptional activation produced sufficient fluorescence for detection with the flow cytometer, especially when there were strong interactions
Assuntos
Genes Reporter , Leveduras/genética , Técnicas do Sistema de Duplo-Híbrido , Sequência de Bases , Clonagem Molecular , Citometria de Fluxo , Dados de Sequência Molecular , Proteínas Luminescentes/análise , Proteínas Luminescentes/genética , Alinhamento de SequênciaRESUMO
1. A study of six patients with Chronic Calcifying Pancreatitis (CCP) occurring over a 10 year period, representing an incidence rate of approximately 1:1,000 of the inpatients in the children's ward of a general hospital in central Brazil, is reported. 2. Major clinical manifestations as well as therapeutic management are described. 3. The possible relationship between CCP and primary protein-calorie malnutrition is discussed and the importance of a CCP diagnosis when dealing with malnourished children who do not respond satisfactorily to common therapy is emphasized.
Assuntos
Pancreatite/etiologia , Desnutrição Proteico-Calórica/complicações , Calcinose/diagnóstico , Calcinose/etiologia , Criança , Pré-Escolar , Doença Crônica , Feminino , Humanos , Masculino , Pancreatite/diagnóstico , Pancreatite/terapiaRESUMO
1. Study of six patients with chronic calcifying pancreatitis (CCP) occurring over a 10 year period, representing an incidence rate of approximately 1:1,000 of the impatients in the children's ward of a general hospital in central Brazil, is reported. 2. Major clinical manifestations as well as therapeutic management are described. 3. The possible relationship between CCP and primary protein-calorie malnutrition is discussed and the importance of a CCP diagnosis when dealing malnourished children who do not respond satisfactorily to common therapy is emphasized
Assuntos
Pré-Escolar , Criança , Humanos , Masculino , Feminino , Calcinose/etiologia , Pancreatite/etiologia , Desnutrição Proteico-Calórica/complicações , Doença Crônica , Estado NutricionalRESUMO
Neste trabalho sao feitas consideracoes sobre a doenca celiaca. Uma casuistica e apresentada, e a necessidade de se estabelecer criterios bem definidos da doenca e discutida. Enfatiza-se o risco de complicacoes que correm os celiacos em uso de gluten. Manifestacoes clinicas pouco comuns e outras menos evidentes sao abordadas no trabalho o efeito protetor do leite humano e enfatizado
