The FUT2 genes encoding for the phenotypes Le(a+b+) and Le(a+b-) are the same. The function and character of the mutant enzyme may play an important role in the phenotype. The methods used in this study are clinically applicable in population studies of the FUT2 gene polymorphism to explore relationships among different ethnic groups and correlations between phenotype and genotype.

The Lewis (Le) blood type comprises two major antigens, Le(a) and Le(b), which are encoded by alpha (1,2)-fucosyltransferase (FUT2) and a (1,3/1,4)-fucosyl-transferase (FUT3). In this study, we analyzed the mutations of FUT3 in Taiwanese, Thai, and Filipino populations and correlated these with serologic phenotypes. One hundred and thirty-seven Taiwanese, 71 Thai, and 125 Filipino were studied unselectively. The frequency of the normal and four other mutant alleles for Taiwanese, Thai, and Filipino, respectively, were as follows: 187/274 (68.2%), 87/142 (61.3%), and 160/250 (64.0%) were wild type (Le); 14/274 (5.1%), 1/142 (0.7%), and 1/250 (0.4%) were a T202C/C314T mutation (le202,314); 35/274 (12.8%), 15/142 (10.6%), and 22/250 (8.8%) had the G508A mutation (le508); and 38/274 (13.9%), 39/142 (27.4%), and 67/250 (26.8%) carried the T1067A mutation (le1067). The le445 and le1007 were not detected in this study. Our result provided the first genetic data of the FUT3 gene in these three populations, and the frequency distribution of mutant alleles among Taiwanese, Thai, and Filipinos demonstrates a significant difference (P<0.001). In our study, the le202,314 mutation had considerable frequency in the Taiwanese, but the le1067 mutation had a higher frequency in Thai and Filipinos.