CORRELATION OF A MISSENSE MUTATION IN THE HUMAN SECRETOR ALPHA-1,2-FUCOSYL-TRANSFERASE GENE WITH THE LEWIS(A+B+) PHENOTYPE - A POTENTIAL MOLECULAR-BASIS FOR THE WEAK SECRETOR ALLELE (SE-W)

A missense mutation (A(385) to T), predicting an Ile(129) to Phe substitution, in the human Secretor alpha 1,2-fucosyltransferase gene was present in double dose in Lewis(a + b +) individuals, but not in Lewis(a - b +) individuals. Co-segregation of the Lewis(a + b +) phenotype with homozygosity for the mutation was also verified. These results yield a potential molecular basis for the weak Secretor allele (Se-w) accounting for the Lewis(a + b +) phenotype.