Homozygous expression of a missense mutation at nucleotide 385 in the FUT2 gene associates with the Le(a+b+) partial-secretor phenotype in an Indonesian family.

A new point mutation was found in the coding sequence of the secretor FUT2 gene. This missense mutation with an A-->T substitution at nucleotide 385 resulted in an amino acid change of Ile129 to Phe129. This mutation showed a clear genetic trait in an Indonesian pedigree and, when appearing in a homozygous form, it was associated with the red cell Le(a+b+) and salivary partial-secretor phenotype. This result suggests that the molecular basis for the Le(a+b+) and associated partial-secretor phenotype is caused by a partially inactivating amino acid change in the alpha(1,2)fucosyltransferase coded for by this new FUT2 allele.