Background: The Bombay and para-Bombay phenotypes arise from mutations of the FUT1 gene that silence the gene or affect the efficiency of the encoded 2-alpha-fucosyltransferase. Samples from seven individuals of different geographic backgrounds whose red blood cells had an apparent Bombay or para-Bombay phenotype were investigated. Among these, novel FUT1 and FUT2 alleles were identified.
Study design and methods: Standard serologic techniques were used. Genomic DNA was sequenced with primers that amplified the coding sequence of FUT1 and the related secretor gene, FUT2. Routine ABO genotyping analysis was performed.
Results: Five new FUT1 alleles were identified that silenced FUT1 or weakened alpha2FucT1 activity. These were 35C>T, 269G>T (Ala11Val, Gly89Val); 421A>G (Trp140Stop); 538C>T, 1089T>G (Gln180Stop, Ala363Ala); 689A>C (Gln230Pro); and 917C>T (Thr305Ile). In addition, both homozygosity and heterozygosity for the previously reported mutation, 826C>T (Gln276Stop), were observed. Four of seven samples were homozygous for the silencing mutation 428A in FUT2. One new FUT2 allele was identified: 278C>T, 357C>T (Ala93Val, Asn119Asn).
Conclusions: These results add to the growing database of apparently sporadic and random mutations in the FUT1 gene and confirm previous reports regarding the lack of ethnic bias. In contrast, our data reinforce the apparent maintenance of the common nonsecretor FUT2 alleles in the population.