Five novel missense mutations of the Lewis gene (FUT3) in African (Xhosa) and Caucasian populations in South Africa

H. Pang, Yuhua Liu, Yoshiro Koda, Mikiko Soejima, Jingtao Jia, Terry Schlaphoff, Ernette D. du Toit, H. Kimura

Five novel missense mutations, viz., C304 A, T370 G, G484 A, G667 A, and G808 A, in the Lewis gene (FUT3) were detected in African (Xhosa) and Caucasian individuals in South Africa. These single base substitutions may result in changes in amino acid residues from Gln102 to Lys in the 304 mutation, Ser124 to Ala in the 370 mutation, Asp162 to Asn in the 484 mutation, Gly223 to Arg in the 667 mutation, and Val270 to Met in the 808 mutation. Out of the five novel mutations identified in this investigation, four new alleles (le484,667, le484,667,808, Le304, and Le370) were determined in the Xhosa population and two new alleles (le202,314,484 and Le304) in the Caucasian population. The determination of alpha(1,3/1,4)fucosyltransferase activity, after transfection of plasmids containing the new alleles into COS7 cells, suggested that alleles le484,667 and le484,667,808 encoded an inactive enzyme, and that alleles Le304 and Le370 encoded a functional enzyme. In addition, we also examined the incidence of five common alleles, Le59, le59,508 le59,1067, le202,314, and le1067 in two populations by the polymerase chain reaction/restriction fragment length polymorphism method and compared differences in the allele frequencies of FUT3 among three ethnic groups (Orientals, Africans, and Caucasians).