Ethnic variation of the C677T and A1298C polymorphisms in the methylenetetrahydrofolate-reductase (MTHFR) gene in southwestern Mexico

Abstract

ABSTRACT. In this study, we examined the distribution of genotype and allele frequencies of the C677T and A1298C polymorphisms in the methylenetetrahydrofolate-reductase gene (MTHFR) in two ethnic groups in the State of Guerrero, Mexico, which were compared with those of the Mestizo population of the region. A comparative study was conducted on 455 women from two ethnic groups and a group of Mestizo women of the State of Guerrero, Mexico: 135 Nahuas, 124 Mixtecas, and 196 Mestizas. Genotyping of both polymorphisms were performed by using polymerase chain reaction-restriction fragment length polymorphism methods. We found that the 677TT genotype was more frequent in Nahua and Mixteca women compared to Mestiza women (P = 0.008), and the most prevalent genotype in both ethnic groups was the 1298AA genotype (P < 0.001). We also compared Ethnic variation of MTHFR polymorphisms in Mexico the 677T allele frequency obtained from the groups studied with the frequencies reported in other ethnic groups of Mexico (Huichol, Tarahumara, and Purepecha). There were significant differences between the three ethnic groups compared to Nahuas (Huicholes, P = 0.004; Tarahumaras, P < 0.001; Purepechas, P = 0.042). Our results indicated significant differences in the frequencies of the C677T and A1298C polymorphisms between the two ethnic groups and the Mestizo population of the State of Guerrero. In addition, we found strong differences with other ethnic groups in Mexico. These results could be useful for future studies investigating diseases related to folate metabolism, and could help the government to design specific nutrition programs for different ethnic groups.

Gene of Folate Cycle MTHFR and Nutrition

“…[18]. Например, минорная Т-аллель локуса 677С>T наиболее распространена среди жителей Италии и Мексики, в культуре питания которых значимый удельный вес занимает растительная пища [15]. Вместе с тем данные популяции характеризуются сбалансированным питанием, включающим растительные, мясные и морепродукты.…”

Heterogenous Distribution of MTHFR Gene Variants among Mestizos and Diverse Amerindian Groups from Mexico

“…Both polymorphisms have been associated with reduced enzyme activity, particularly the C677T polymorphism, which imparts thermolability to the enzyme [ 2 , 3 ]. Worldwide studies of these variants have shown that the Mexican Mestizo population has the highest frequency of the 677T allele (44–61%), and the lowest frequency of the 1298C allele (7–11.7%) [ 4 – 8 ]. In particular, the C677T polymorphism has been implicated in several diseases, including neural tube defects (NTDs), cardiovascular diseases, hypertension and various types of cancer, among others [ 4 , 9 – 14 ].…”

“…Previous studies have suggested that the Amerindian genome has largely contributed to the presence of the 677T allele in the Mexican-Mestizo population [ 7 , 8 , 13 , 16 ]. Most of Mexicans are a mixed population derived mainly from Amerindian, European, and African ancestries, whose proportion vary largely across the country, with a clear increasing Amerindian ancestry gradient from North to South [ 17 , 18 ].…”

“…Additionally, 14.9% of the Mexican population is indigenous, distributed in 68 different ethnic groups [ 19 , 20 ]. Despite the relevance of the MTHFR C677T variant in populations with an Amerindian origin, genetic studies have explored only about 10% of the ethnic groups recognized by the Mexican Indigenous Languages Institute (INALI) [ 7 , 8 , 13 , 16 , 20 ]. Moreover, very few studies have examined the A1298C variant in the Mexican population, even in the Mestizo population.…”

Interactions among methylenetetrahydrofolate reductase (MTHFR) and cystathionine β-synthase (CBS) polymorphisms - a cross-sectional study: multiple heterozygosis as a risk factor for higher homocysteine levels and vaso-occlusive episodes

“…Albeit frequent in different populations, these polymorphisms have shown great ethnic and geographical variability (Sebastio et al, 1995;Franco et al, 1998;Franco et al, 1999;Dilley et al, 2001;Franco and Reitsma, 2001;Miranda-Vilela, 2012;Antonio-Véjar et al, 2014). As the Brazilian population is very mixed, primarily from five centuries of interethnic crosses among Europeans, Africans and Amerindians, and this miscegenation can influence the distribution of certain polymorphisms (Lordelo et al, 2012;Barbosa et al, 2014), the objective of this study was to investigate the role of MTHFR (C677T, A1298C) and CBS (T833C/844ins68, CBS G919A) polymorphisms in serum levels of folic acid, vitamin B12 and Hcy in Brazilian patients with a diagnosis of thrombosis, and to verify a possible association between these polymorphisms and the clinical variability.…”