RESUMEN
OBJECTIVE: Polymorphisms that reduce the activity of reduced folate carrier (RFC) and methylenetetrahydrofolate reductase (MTHFR) and double (2R2R) or triple (3R3R) 28-bp tandem repeats in the promoter region of thymidylate synthase (TS) have been associated with the risk of childhood acute leukemia (AL). A case-control genotyping study was conducted in Brazilian children with the aim of investigating RFC, MTHFR, and TS polymorphisms as risk factors. METHODS: The polymerase chain reaction-restriction fragment length polymorphism method was employed in 177 AL cases and 390 controls. RESULTS: The presence of the mutant 1298C, also RFC 80A, was linked to a decreased risk of developing acute lymphoid leukemia (ALL) (odds ratio (OR)=0.46, 95% confidence interval (CI)=0.30-071 and OR=0.51, 95% CI=0.28-0.0.93, respectively). CONCLUSIONS: The genotype 677 CT was associated with increased risk of developing ALL (OR=1.6, 95% CI=1.1-2.7). Further epidemiological study is needed to unravel the role of complex multiple gene-environment interactions in leukemogenesis.
Asunto(s)
Ácido Fólico/metabolismo , Metilenotetrahidrofolato Reductasa (NADPH2)/genética , Polimorfismo Genético , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteína de Replicación C/genética , Timidilato Sintasa/genética , Adolescente , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Genotipo , Humanos , Masculino , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Riesgo , Adulto JovenRESUMEN
OBJECTIVE: To investigate the association between total plasma homocysteine concentration, C677T and A1298C polymorphisms in MTHFR gene and Alzheimer's disease (AD) development. METHOD: Forty-three patients with probable (63 percent) and possible (37 percent) AD and 50 non-demented controls were evaluated. Groups did not differ as to gender, age, scholar years, diabetes, alcohol and coffee intake and physical activity. Total plasma homocysteine (Hcy) levels were determined by HPLC and genotyping for MTHFR by PCR/RFLP. Mann-Whitney "U" test was used to compare quantitative variable, Fisher-Freeman-Halton test to compare genotypes and allele proportions and Chi-square test to other qualitative variables. RESULTS: AD patients presented higher total plasma Hcy levels than controls and the difference was statistically significant. No differences in the C677T and A1298C MTHFR polymorphisms distributions were found between patients and controls. Plasma homocysteine concentration did not change with MTHFR genotypes. CONCLUSION: Our data confirms the association between increased plasma Hcy concentration and AD and suggests that neither C677T nor A1298C MTHFR polymorphisms contributed to genetic susceptibility for AD in elderly individuals in the Northeast of Brazil.
OBJETIVO: Investigar a associação entre a concentração plasmática total de homocisteína (Hcy), os polimorfismos C677T e A1298C do gene MTHFR e o desenvolvimento da Doença de Alzheimer (AD). MÉTODO: Foram avaliados 43 pacientes com doença de Alzheimer possível (37 por cento) e provável (63 por cento) e 50 controles não dementes, não divergentes quanto ao sexo, idade, anos de escolaridade, diabetes, consumo de álcool e de café e vida sedentária. Os níveis plasmáticos de homocisteína foram determinados por HPLC e a genotipagem para MTHFR por PCR/RFLP. A comparação dos níveis de homocisteína foi realizada pelo teste "U" Mann-Whitney, a comparação das proporções dos genótipos e alelos pelo teste de Fisher-Freeman-Halton e as demais variáveis qualitativas, pelo teste do qui-quadrado. RESULTADOS: Os pacientes AD apresentaram níveis mais elevados de Hcy plamática total do que os controles e a diferença entre os grupos foi estatisticamente significante. Não houve diferença nas distribuições genotípicas C677T e A1298C entre pacientes e controles. A concentração de Hcy não variou com os genótipos. CONCLUSÃO: Nossos dados confirmam a associação de concentração elevada de Hcy plasmática com DA e sugerem que os polimorfismos C677T e A1209C não contribuem para a susceptibilidade genética a DA em idosos do Nordeste do Brasil.
Asunto(s)
Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Alzheimer/sangre , Enfermedad de Alzheimer/genética , Homocisteína/sangre , /genética , Polimorfismo Genético , Estudios de Casos y Controles , Marcadores Genéticos , Predisposición Genética a la Enfermedad , Genotipo , Homocisteína/metabolismo , /metabolismoRESUMEN
OBJECTIVE: To investigate the association between total plasma homocysteine concentration, C677T and A1298C polymorphisms in MTHFR gene and Alzheimer's disease (AD) development. METHOD: Forty-three patients with probable (63%) and possible (37%) AD and 50 non-demented controls were evaluated. Groups did not differ as to gender, age, scholar years, diabetes, alcohol and coffee intake and physical activity. Total plasma homocysteine (Hcy) levels were determined by HPLC and genotyping for MTHFR by PCR/RFLP. Mann-Whitney "U" test was used to compare quantitative variable, Fisher-Freeman-Halton test to compare genotypes and allele proportions and Chi-square test to other qualitative variables. RESULTS: AD patients presented higher total plasma Hcy levels than controls and the difference was statistically significant. No differences in the C677T and A1298C MTHFR polymorphisms distributions were found between patients and controls. Plasma homocysteine concentration did not change with MTHFR genotypes. CONCLUSION: Our data confirms the association between increased plasma Hcy concentration and AD and suggests that neither C677T nor A1298C MTHFR polymorphisms contributed to genetic susceptibility for AD in elderly individuals in the Northeast of Brazil.
