The Lewis histo-blood group system: molecular analysis of the 59T>G, 508G>A, and 1067T>A polymorphisms in an Amazonian population.
BACKGROUND
The Lewis (FUT3) gene is responsible for the expression of the Le(a) and Le(b) blood group antigens. The individuals, who not synthesize these antigens have the phenotype Lewis negative, due to the presence of some single nucleotide polymorphisms (SNPs), such as 59T>G, 508G>A and 1067T>A, whose distribution is different in various ethnic groups. Our aim was to verify the frequencies of these SNPs in an admixed population of Belém-Pará-Brazil.


METHODS
Polymerase chain reaction/restriction enzyme method were used to detect these SNPs in the FUT3 gene, whereas Lewis phenotypes were defined by the direct hemagglutination and in saliva by Dot-Elisa assay in a random sample of 150 individuals from admixed population of Belém in the northeast Brazilian Amazon region.


RESULTS
The frequency of these SNPs was detected as 47.6% (59T>G), 17.3% (508G>A) and 5.3% (1067T>A).The discrepancies between blood and salivary Lewis phenotypes are related to the relatively high frequencies of 59T>G and the null allele 508G>A. Whereas 38.6% of the individuals were Lewis negative based on blood, only 17.24% also tested negative when their saliva were analyzed.


CONCLUSIONS
We have found a marked consistency between the phenotypes and genotypes of the Lewis blood group system. Furthermore, our obtained FST values reveal distinct frequencies of the FUT3 SNPs between the present sample and its representative ancestral populations. These observations will help to evaluate the Lewis antigens impact as susceptibility markers, in genetic association studies to certain diseases.
Immunogenetics Laboratory, Biological Sciences Institute, Federal University of Pará, Belém, Pará, Brazil. tereza@ufpa.br
Tereza Cristina de Oliveira
TC
Corvelo
Rosane do Socorro Pompeu
Rdo S
de Loiola
Délia Cristina Figueira
DC
Aguiar
Gyselly de Cássia Bastos
Gde C
de Matos
Danielle Calado
DC
de Brito
D000328:Adult; D005260:Female; D005647:Fucosyltransferases / Q000235:genetics*; D005838:Genotype; D006801:Humans; D007983:Lewis Blood Group Antigens / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D055815:Young Adult
D007983:Lewis Blood Group Antigens; D005647:Fucosyltransferases; C019818:3-galactosyl-N-acetylglucosaminide 4-alpha-L-fucosyltransferase