Molecular characterization of secretor type alpha(1,2)-fucosyltransferase gene deficiency in the Philippine population

We analyzed the seven mutations which are responsible for the deficiency of the secretor type alpha(1,2)-fucosyltransferase gene product, Se enzyme, i n the Philippine population. One hundred and one unrelated Filipinos in Tai wan were studied. A new mutation, a 3-base pair deletion from nt 688 throug h 690, was found in two (0.1%) of 202 chromosomes. The frequencies of six o ther mutated alleles were as follows: 71/202 (35.2%) were cDNA 385 A-->T mi ssensed mutation (se2), 28/202 (13.9%) were C571T nonsense mutation (se3), 16/202 (7.9%) were G849A nonsense mutation (se4), 4/202 (1.9%) were G328A n onsense mutation (se1), and 81/202 (40.1%) were wild-type allele (Se). No C 628T nonsense mutations (se5) or fusion genes of pseudogene and FUT2 gene ( se 6) were found in this population. For the molecular basis of phenotype L e(a + b-): eight cases had se2/se2, six cases had se2/se3, two cases had se 3/se4, one case was homozygous of se4, one case was se3/se1, and two cases were se2/se7. For the Le(a + b +) phenotype: four cases had se2/se2, two ca ses had se2ise3, one case was se3/se3, and one case was se2/se4. For the Le (a - b +) phenotype: 16 cases were Se/Se, 21 cases were Se/se2, six cases w ere Se/se3, five cases were Se/se4, and two cases had Se/se1. Our results s uggest that the genotypes of the alpha(1,2)-fucosyltransferase gene in phen otypes Le(a + b +) and Le(a + b -) are the same. Other factors that play im portant roles may cause the differences between these two phenotypes. Sever al hotspot mutations in the alpha(1,2)-fucosyltransferase gene are responsi ble for the nonsecretor phenotype.