Analysis of the 677 C→T Mutation of the Methylenetetrahydrofolate Reductase Gene in Different Ethnic Groups

Abstract

SummaryA recently described mutation in the methylenetetrahydrofolate reductase (MTHFR) gene (a C to T transition at nucleotide 677) is associated with a thermolabile phenotype and decreased enzyme activity. In homozygotes, the mutation is also related to hyperhomocysteinemia and increased risk for atherosclerotic disease and (apparently) venous thrombosis. The prevalence of this mutation in different human populations is unknown. We have investigated the frequency of the 677 C→T mutation in the MTHFR gene in 337 individuals (674 chromosomes) belonging to four ethnic groups: Whites, African and Brazilian Blacks, Asians and Amerindians. The frequencies of the positive allele among Whites and Asians were similar to those previously reported for Caucasian populations. The positive allele seems to be slightly rarer among the Amerindians (frequency 24.0%) in comparison to Whites and Asians, with a heterogeneous distribution among the five Indian tribes analysed. In contrast, the mutation has a very low prevalence in Blacks, especially among the African Blacks, for whom the mutation was absent in homozygosity. Our data indicate that the 677 C→T MTHFR mutation has a significantly heterogeneous distribution among different ethnic groups, a fact that may contribute to explain geographical or racial differences in the risk for vascular disease.

Methylenetetrahydrofolate Reductase (MTHFR C677T) Polymorphism in Sudanese Patients with Deep Vein Thrombosis

“…The T allele frequency ranges from 0.06 to 0.59 and the frequency of the T/T genotype (homozygosity for the C677T mutation) ranges from 0.00 to 0.35 among ethnic populations [18]. Our study showed low frequency of mutant MTHFR C677T genotype with 0%TT genotype (homozygote) & 12% CT (heterozygote) our finding is similar with previous reports among different study population in Africa [19,20].…”

Methylenetetrahydrofolate Reductase (MTHFR) Allele Frequencies in Amerindians

“…b While Schneider et al (1998) did not specify the origin of the groups studied, since the samples had been provided by J.F. Guerreiro they should be of the Amazonian region; Franco et al (1998) indicated that samples from the Wayampi, Wayana-Apalai, Kayapo, Arara, and Yanomami tribes had been pooled for their study.…”

Primary prevention of neural tube defects in Brazil: insights into anencephaly

“…Other folates and NTD-related genes, such as methylenetetra-hydrofolate dehydrogenase (MTHFD), have not been evaluated in Brazilian population yet. Brazilian antecedents on the prevalence of the 677C>T mutation came from different populations and ethnic groups and in general, they indicated a prevalence below 10 % of TT homozygous individuals and higher prevalence of the mutation in individuals with European than African or Amerindian ancestry (Ferreira-Fernandes et al 2013;Franco et al 1998;Brandalize et al 2007;Arruda et al 1998). …”