Novel mutations, including a novel G659A missense mutation, of the FUT1 gene are responsible for the para-Bombay phenotype.

Para-Bombay phenotype, with an estimated incidence of 1 in 8000 in Taiwanese residents based on serological analysis, is caused by aberrant alpha(1,2)-fucosyltransferase function and hence diminished H-antigen synthesis. In an individual with para-Bombay phenotype, DNA sequencing revealed two missense mutations previously reported C658T mutation and a novel G659A mutation. Haplotype analysis with restriction enzyme digestion showed that the two mutations are located on opposing alleles of the H (FUT1) gene and lead to compound heterozygosity. Since no other known genetic changes were evident, it appears that the new missense mutation, G659A, is deleterious to the alpha(1,2)-fucosyltransferase function encoded by the H (FUT1) gene.