The Frequency of the LCT * –13910C T Polymorphism Associated with Lactase Persistence Diverges among Euro-Descendant Groups from Brazil

Objective: The aim of this study was to investigate the frequency of the LCT * –13910C T polymorphism associated with a high expression of lactase in the small intestine during adulthood, and to infer the lactase persistence and adult-type hypolactasia phenotypes among Euro-Brazilians and Mennonites from South Brazil. Materials and Methods: A sequence-specific PCR method to genotype the LCT * –13910C T polymorphism in 292 Euro-Brazilians and 151 Mennonites (a group with European ancestry and a long history of endogamy) was developed. Using an exact test of population differentiation, the genotype and allele frequency between these and other Brazilian populations were compared. Results: The frequency of –13910 * T was significantly higher among the Mennonites when compared to the Euro- Brazilian cohort (0.63 vs. 0.33, p 0.000001). Accordingly, Mennonites had a higher prevalence of the lactase persistence genotype (88.1 vs. 55.5%, p 0.000001). The distribution of –13910 * T differed between Mennonites and all other Brazilian groups (p 0.0001). The Euro-Brazilians from Curitiba displayed differences when compared to all other Brazilian groups (p 0.0001), even to Euro-Brazilians from a different geographic region (p = 0.0003), but were similar to those from Porto Alegre (p = 0.2). Conclusion: Differences in the –13910 * T- associated lactase persistence distribution among Euro-Brazilian groups reflect the ancestry and admixture of each particular group and should be considered for adulttype hypolactasia screening.