Frequencia das principais mutações no gene da cistationina beta sintetase em portadoras de sindrome de turner e mães de portadores de Sindrome de Down

AUTOR(ES)

Erika Lourenço Pollice

DATA DE PUBLICAÇÃO

2003

RESUMO

The most common class of chromosome abnormality is Down Syndrome (DS) and Turner Syndrome (TS). Several investigators have reported that mutations in the metabolic homocysteine enzymes are associated with increased risk of chromosome abnormality due the hypometilation phenomena. The main enzymatic regulators in the metabolism of the homocystheine are Cystathionine beta-Synthase (CBS) and methylenetetrehydrofolate reductase (MTHFR.). It is important to note that tissues deficient of CBS, are waited to be more sensible to revert SAHH and to increase SAR. Recent studies shown that the mcrease of SAR m parallel with homocystheine, in healthful young women was associated with DNA hypomethilation. The CBS gene was mapped in the chromosome 21q22.3, has approximately 25 Kb and 23 exons. The majority mutations the CBS gene are missense. Two mutations, the I278T and G307S are said as more frequento Another mutation ftequently found m caucasians is 844ins68. We analyzed the frequency of the mutations 844ins68, G307S and I278T m the gene of the CBS. The analysis method was the Polymerase ChaID Reaction (PCR) associated with an restriction enzyme. The prevalence of the CBS mutations was determmed m 81 mothers of DS patients (MDS), 53 patients with TS and 80 healthy women. In TS patients, the 844ins68 were 0.09, G307S, 0.05 and I278T, 0.08. In MDS, the ftequencies ofthe mutations were respective: 0.09, 0.05 e 0.09. The mutations were found m a statistically identical prevalence among control and test groups. When these findIDgs were related to MTHFR genotypes, they did not show any preferential association. In this study the only finding were the higher prevalence of C677T/A1298C of MTHFR, indicating that this composition increased the risk factor for DS

ASSUNTO(S)

aneuploidia enzimas metionina

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