Resumo

BERMUDEZ, Marta; BRICENO, Ignacio; GIL, Fabián  e  BERNAL, Jaime. Homocysteine and polymorphisms of cystathionine synthase and methylenetetrahydrofolate reductase in a healthy population from Colombia. Colomb. Med. [online]. 2006, vol.37, n.1, pp.46-52. ISSN 1657-9534.

Introduction: Recently, moderate hyperhomocysteinemia (>17 mM) and the presence of polymorphic variants of the genes involved in methionine metabolism as cystathionine b synthase (CBS) and 5,10-methylenetetrahydrofolate reductase (MTHFR) have been associated with vascular disease. Objectives: The aims of this study were to quantify basal and post methionine load levels of homocysteine in a Colombian healthy population and to identify the frequencies of the allelic variants c.699 C >T (exon 6), c.1080 C>T (exon 10) of CBS, and c.677 C>T (exon 1) of MTHFR. Association studies between these allelic variants and hiperhomocisteinemia were performed. Methods: A group of 102 healthy individuals, without geographic origin, ethnic group or social-economic stratification were studied for polymorphisms c.699 C >T (CBS exon 6), c.1080 C>T (CBS exon 10) and c.677 C>T (MTHFR exon 1) by restriction analysis and the allele frequencies were calculated. Association study was performed using Fisher exact test. Results: Quantification of basal homocysteine levels (10.52 mM + 5.8) and after methionine load (30.14 +16, 20) was performed. Among individuals 8 were identified with moderate hyperhomocysteinemia, one having basal and the seven post methionine load. Post methionine load in males produced values of 32.43 + 8.64 and were significantly different from that of females (p=0.006) who had values of 28.03 + 7.02. Our results showed that homozygous individuals (TT) for the 677 C/T variant have a risk of 5.14 (odds ratio, p=0.034) of being hyperhomocysteinemic. Conclusions: Hyperhomocysteinemic patients were identified by methionine load test. A positive association between homozygous of the polymorphism 677 of MTHFR was found. The frequency of this polymorphism in Colombia is the highest reported in the literature.

Palavras-chave : Hyperhomocysteinemia; Vascular disease; Metilenetetrahidrofolato reductasa; Cistationine ß sintase; Polymorphisms.

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