A newly identified nonsecretor allele of the human histo-blood group alpha(1,2)fucosyltransferase gene (FUT2).

BACKGROUND AND OBJECTIVES

The human Secretor alpha(1, 2)fucosyltransferase gene determines the ABH secretor status and influences the Lewis phenotype of an individual. Studies were carried out on the Lewis (a+b-) nonsecretors of different groups indigenous to Taiwan to demonstrate their se genotypes.

METHODS

The Lewis phenotype of the blood samples was determined by a microplate method. The se genotypes of the individuals with the Lewis (a+b-) phenotype were analyzed by a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method designed for the se alleles reported previously. PCR and cloning techniques were used to determine the coding sequence of the novel se gene.

RESULTS

A new se allele, se685, with a three-nucleotide deletion of GTGGT to GT in the coding region of nucleotides 685 through 689 was identified in a Le (a+b-) nonsecretor from the Ami tribe indigenous to Taiwan. The deletion predicts the loss of the amino acid Val230 in the corresponding secretor enzyme's C-terminal segment. The distribution of the se685 allele in the Ami tribe was further verified by PCR-RFLP analysis.

CONCLUSION

The Se gene exhibits heterogeneity with some Se alleles being common but others displaying a unique distribution in different ethnic populations. The newly identified se685 allele seems to exist only in the Ami tribe indigenous to Taiwan.